Editing Perjury (section)

== Perjury law by jurisdiction ==
===Australia===
Perjury is punishable by imprisonment in various states and territories of Australia. In several jurisdictions, longer prison sentences are possible if perjury was committed with the intent of convicting or acquitting a person charged with a serious offence.

* Australian Capital Territory: Perjury is punishable by a fine of up to AU$112,000 or 7 years imprisonment or both.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/act/consol_act/cc200294/s703.html |title=Criminal Code 2002 - Sect 703 Perjury |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref><ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/act/consol_act/la2001133/s133.html |title=Legislation Act 2001 - Sect 133 Penalty units |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref> If perjury was committed with the intent of convicting or acquitting someone of an offence which carries a prison sentence, the maximum penalty is AU$224,000 or 14 years imprisonment or both.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/act/consol_act/cc200294/s702.html |title=Criminal Code 2002 - Sect 702 Aggravated perjury |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* New South Wales: Under Section 327 of the [[Crimes Act 1900]], perjury is punishable by imprisonment of up to 10 years.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/nsw/consol_act/ca190082/s327.html |title=Crimes Act 1900 - Sect 327 Offence of perjury |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref> Under Section 328, if a person commits perjury with the aim of convicting or acquitting a person charged with an offence that carries a prison sentence of 5 years or more, perjury is punishable by imprisonment of up to 14 years.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/nsw/consol_act/ca190082/s328.html |title=Crimes Act 1900 - Sect 328 Perjury with intent to procure conviction or acquittal  |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* Northern Territory: Perjury is punishable by imprisonment of up to 14 years. If perjury was committed to convict someone of an offence that carries life imprisonment, the perjurer can be imprisoned for life.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/nt/consol_act/cca1983115/sch1.html |title=Criminal Code Act 1983 - Schedule 1  |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* Queensland: Perjury is punishable by imprisonment of up to 14 years. If perjury was committed to convict someone of an offence that carries life imprisonment, the perjurer can be imprisoned for life.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/qld/consol_act/cc189994/s124.html |title=Criminal Code 1899 - Sect 124 Punishment of perjury |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* South Australia: Perjury and [[subornation of perjury]] is punishable by imprisonment of up to 7 years.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/sa/consol_act/clca1935262/s242.html |title=Criminal Law Consolidation Act 1935 - Sect 242 |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* Tasmania: Perjury is a crime in Tasmania.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/tas/consol_act/cc192494/s94.html |title=Criminal Code 1924 - Sect 94 Perjury |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* Victoria: Perjury and [[subornation of perjury]] is punishable by imprisonment of up to 15 years.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/vic/consol_act/ca195882/s314.html |title=Crimes Act 1958 - Sect 314 Perjury  |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

* Western Australia: Under Section 125 of the Criminal Code Act Compilation Act 1913, perjury is punishable by imprisonment of up to 14 years. If perjury was committed to convict someone of an offence that carries life imprisonment, the perjurer can be imprisoned for life.<ref>{{cite web |url=https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/wa/consol_act/ccaca1913252/notes.html |title=Criminal Code Act Compilation Act 1913 - Notes |website=Australasian Legal Information Institute |access-date=24 April 2022}}</ref>

===Canada===
{{See also|b:Canadian Criminal Sentencing/Offences/Perjury}}

The offence of perjury is codified by section 132 of the [[Criminal Code (Canada)|Criminal Code]]. It is defined by section 131, which provides:

{{Blockquote|(1) Subject to subsection (3), every one commits perjury who, with intent to mislead, makes before a person who is authorized by law to permit it to be made before him a false statement under oath or solemn affirmation, by affidavit, solemn declaration or deposition or orally, knowing that the statement is false.<br/>
(1.1) Subject to subsection (3), every person who gives evidence under subsection 46(2) of the [[Canada Evidence Act]], or gives evidence or a statement pursuant to an order made under section 22.2 of the [[Mutual Legal Assistance in Criminal Matters Act]], commits perjury who, with intent to mislead, makes a false statement knowing that it is false, whether or not the false statement was made under oath or solemn affirmation in accordance with subsection (1), so long as the false statement was made in accordance with any formalities required by the law of the place outside Canada in which the person is virtually present or heard.<br/>
(2) Subsection (1) applies, whether or not a statement referred to in that subsection is made in a judicial proceeding.<br/>
(3) Subsections (1) and (1.1) do not apply to a statement referred to in either of those subsections that is made by a person who is not specially permitted, authorized or required by law to make that statement.<ref>[[Criminal Code (Canada)|Criminal Code]], [http://laws-lois.justice.gc.ca/eng/acts/C-46/page-74.html#docCont RSC 1985, c C-46, s 131], as amended by RSC 1985, c 27 (1st Supp.), s 17, and SC 1999, c 18, s. 92.</ref>}}

As to corroboration, see section 133.

Everyone who commits perjury is guilty of an [[indictable offence]] and liable to imprisonment for a term not exceeding fourteen years.<ref name=":0">Criminal Code, [http://laws-lois.justice.gc.ca/eng/acts/C-46/page-74.html#s-132. s 132, as amended by RSC 1985, c 27 (1st Supp), s 17 and SC 1998, c 35, s 119.]</ref>

===European Union===
A person who, before the [[Court of Justice of the European Union]], swears anything which they know to be false or do not believe to be true are, whatever their nationality, guilty of perjury.<ref>The [[Court of Justice of the European Communities (Perjury) Act 1975]], [http://www.irishstatutebook.ie/1975/en/act/pub/0012/sec0001.html section 1]</ref> Proceedings for this offence may be taken in any place in the State and the offence may for all incidental purposes be treated as having been committed in that place.<ref>The [[Court of Justice of the European Communities (Perjury) Act 1975]], [http://www.irishstatutebook.ie/1975/en/act/pub/0012/sec0002.html section 2]</ref>

===India===

"The offence of perjury finds its place in law by virtue of Section 191 to Section 203 of the Indian Penal Code, 1860 ('IPC'). Unlike many other countries, the offence of perjury is muted on account of Section 195 of the Code of Criminal Procedure, 1973 ("Cr.P.C"). Section 195(1)(b)(i) of the Cr.P.C. restricts any court to take cognisance of an offence of perjury unless the same is by way of a complaint in writing by the court before which the offence is committed or by a superior court."<ref>{{cite web|url=https://www.lawyersclubindia.com/articles/perjury-important-case-laws-showing-how-seriously-it-is-taken-in-india--11013.asp|title=Case law showing how seriously perjury is taken in India.|date=18 February 2020 }}</ref>

===New Zealand===
Punishment for perjury is defined under Section 109 of the [[Crimes Act 1961]].<ref>{{cite web |url=http://www.nzlii.org/nz/legis/consol_act/ca196182/ca196182.html |title=Crimes Act 1961 |website=New Zealand Legal Information Institute |access-date=24 April 2022}}</ref> A person who commits perjury may be imprisoned for up to 7 years. If a person commits perjury to procure the conviction of someone charged with an offence that carries a maximum sentence of not less than 3 years' imprisonment, the perjurer may be imprisoned for up to 14 years.

===Nigeria===
{{main|Perjury in Nigeria}}

===United Kingdom===

====England and Wales====
Perjury is a statutory offence in [[England and Wales]]. It is created by section 1(1) of the [[Perjury Act 1911]]. Section 1 of that Act reads:

{{Blockquote|(1) If any person lawfully sworn as a witness or as an interpreter in a judicial proceeding wilfully makes a statement material in that proceeding, which he knows to be false or does not believe to be true, he shall be guilty of perjury, and shall, on conviction thereof on indictment, be liable to [[penal servitude]] for a term not exceeding seven years, or to imprisonment ... for a term not exceeding two years, or to a fine or to both such penal servitude or imprisonment and fine.

(2) The expression "judicial proceeding" includes a proceeding before any court, tribunal, or person having by law power to hear, receive, and examine evidence on oath.

(3) Where a statement made for the purposes of a judicial proceeding is not made before the tribunal itself, but is made on oath before a person authorised by law to administer an oath to the person who makes the statement, and to record or authenticate the statement, it shall, for the purposes of this section, be treated as having been made in a judicial proceeding.

(4) A statement made by a person lawfully sworn in England for the purposes of a judicial proceeding—
:(a) in another part of His Majesty’s dominions; or
:(b) in a British tribunal lawfully constituted in any place by sea or land outside His Majesty’s dominions; or
:(c) in a tribunal of any foreign state,

shall, for the purposes of this section, be treated as a statement made in a judicial proceeding in England.

(5) Where, for the purposes of a judicial proceeding in England, a person is lawfully sworn under the authority of an Act of Parliament—
:(a) in any other part of His Majesty’s dominions; or
:(b) before a British tribunal or a British officer in a foreign country, or within the jurisdiction of the Admiralty of England;

a statement made by such person so sworn as aforesaid (unless the Act of Parliament under which it was made otherwise specifically provides) shall be treated for the purposes of this section as having been made in the judicial proceeding in England for the purposes whereof it was made.

(6) The question whether a statement on which perjury is assigned was material is a question of law to be determined by the court of trial.<ref>{{cite web|url=http://www.legislation.gov.uk/ukpga/Geo5/1-2/6/section/1|title=Perjury Act 1911|work=legislation.gov.uk|access-date=24 July 2015}}</ref>}}

The words omitted from section 1(1) were repealed by section 1(2) of the [[Criminal Justice Act 1948]].

A person guilty of an offence under section 11(1) of the [[European Communities Act 1972 (UK)|European Communities Act 1972]] (i.e. perjury before the [[Court of Justice of the European Union]]) may be proceeded against and punished in England and Wales as for an offence under section 1(1).<ref>The [[European Communities Act 1972 (UK)|European Communities Act 1972]], [http://www.legislation.gov.uk/ukpga/1972/68/section/11 section 11(1)(a)]</ref>

Section 1(4) has effect in relation to proceedings in the Court of Justice of the European Union as it has effect in relation to a judicial proceeding in a tribunal of a foreign state.<ref>The [[Evidence (European Court) Order 1976]] (S.I. 1976/428), [http://www.legislation.gov.uk/uksi/1976/428/article/3/made article 3], as read with [http://www.legislation.gov.uk/uksi/1976/428/article/2/made article 2]</ref>

Section 1(4) applies in relation to proceedings before a relevant convention court under the [[European Patent Convention]] as it applies to a judicial proceeding in a tribunal of a foreign state.<ref>The [[Patents Act 1977]], [http://www.legislation.gov.uk/ukpga/1977/37/section/92 section 92(5)]</ref>

A statement made on oath by a witness outside the United Kingdom and given in evidence through a live television link by virtue of section 32 of the [[Criminal Justice Act 1988]] must be treated for the purposes of section 1 as having been made in the proceedings in which it is given in evidence.<ref>The [[Criminal Justice Act 1988]], [http://www.legislation.gov.uk/ukpga/1988/33/section/32 section 32(3)]</ref>

Section 1 applies in relation to a person acting as an intermediary as it applies in relation to a person lawfully sworn as an interpreter in a judicial proceeding; and for this purpose, where a person acts as an intermediary in any proceeding which is not a judicial proceeding for the purposes of section 1, that proceeding must be taken to be part of the judicial proceeding in which the witness's evidence is given.<ref>The [[Youth Justice and Criminal Evidence Act 1999]], [http://www.legislation.gov.uk/ukpga/1999/23/section/29 section 29(7)]</ref>

Where any statement made by a person on oath in any proceeding which is not a judicial proceeding for the purposes of section 1 is received in evidence in pursuance of a [[special measures direction]], that proceeding must be taken for the purposes of section 1 to be part of the judicial proceeding in which the statement is so received in evidence.<ref>The [[Youth Justice and Criminal Evidence Act 1999]], [http://www.legislation.gov.uk/ukpga/1999/23/section/31 section 31(6)]</ref>

=====Judicial proceeding=====

The definition in section 1(2) is not "comprehensive".<ref name="Archbold Criminal Pleading 1999">[[Archbold Criminal Pleading, Evidence and Practice]]. 1999. Paragraph 28-159 at page 2303.</ref>

The book ''[[Archbold Criminal Pleading, Evidence and Practice|Archbold]]'' says that it appears to be immaterial whether the court before which the statement is made has jurisdiction in the particular cause in which the statement is made, because there is no express requirement in the Act that the court be one of "competent jurisdiction" and because the definition in section 1(2) does not appear to require this by implication either.<ref name="Archbold Criminal Pleading 1999"/>

=====''Actus reus''=====
The ''[[actus reus]]'' of perjury might be considered to be the making of a statement, whether true or false, on oath in a judicial proceeding, where the person knows the statement to be false or believes it to be false.<ref>Ormerod, David. ''Smith and Hogan's Criminal Law''. Thirteenth Edition. Oxford University Press. 2011. Section 4.1.4 at page 49.</ref><ref>Smith, J. C. and Hogan, Brian. ''Criminal Law''. Second Edition. Sweet & Maxwell. 1965. p. 509 footnote 12.</ref>

Perjury is a [[conduct crime]].<ref>Ormerod, David. ''Smith and Hogan's Criminal Law''. Thirteenth Edition. Oxford University Press. 2011. Section 4.1.5.2 at page 50.</ref>

=====Mode of trial=====

Perjury is [[triable only on indictment]].<ref>The [[Perjury Act 1911]], [http://www.legislation.gov.uk/ukpga/Geo5/1-2/6/section/1 section 1(1)]; the [[Magistrates' Courts Act 1980]], [http://www.legislation.gov.uk/ukpga/1980/43/section/17 section 17(1)] and Schedule 1, [http://www.legislation.gov.uk/ukpga/1980/43/schedule/1/paragraph/14 paragraph 14(a)]</ref>

=====Sentence=====

A person convicted of perjury is liable to imprisonment for a term not exceeding seven years, or to a fine, or to both.<ref name=":1">The [[Perjury Act 1911]], [http://www.legislation.gov.uk/ukpga/Geo5/1-2/6/section/1 section 1(1)]; the [[Criminal Justice Act 1948]], [http://www.legislation.gov.uk/ukpga/Geo6/11-12/58/section/1 sections 1(1) and (2)]</ref>

The following cases are relevant:
*''R v Hall'' (1982) 4 [[Criminal Appeal Reports (Sentencing)|Cr App R (S)]] 153
*''R v Knight'', 6 Cr App R (S) 31, [1984] [[Criminal Law Review|Crim LR]] 304, CA
*''R v Healey'' (1990) 12 Cr App R (S) 297
*''R v Dunlop'' [2001] 2 Cr App R (S) 27
*''[http://www.bailii.org/ew/cases/EWCA/Crim/2002/1996.html R v Archer]'' [2002] EWCA Crim 1996, [2003] 1 Cr App R (S) 86
*''R v Adams'' [2004] 2 Cr App R (S) 15
*''R v Cunningham'' [2007] 2 Cr App R (S) 61

See also the Crown Prosecution Service sentencing manual.<ref>{{cite web|url=http://www.cps.gov.uk/legal/s_to_u/sentencing_manual/perjury/|title=Perjury|work=cps.gov.uk|access-date=24 July 2015|archive-url=https://web.archive.org/web/20150923211026/http://www.cps.gov.uk/legal/s_to_u/sentencing_manual/perjury/|archive-date=23 September 2015|url-status=dead}}</ref>

=====History=====
In Anglo-Saxon legal procedure, the offence of perjury could only be committed by both jurors and by [[compurgator]]s.<ref name="Turner421">Turner, J. W. C. ''Kenny Outlines on Criminal Law'' (London: Cambridge University Press, 1964) (18th edition), p.421.</ref> With time witnesses began to appear in court they were not so treated despite the fact that their functions were akin to that of modern witnesses. This was due to the fact that their role were not yet differentiated from those of the juror and so evidence or perjury by witnesses was not made a crime. Even in the 14th century, when witnesses started appearing before the jury to testify, perjury by them was not made a punishable offence. The maxim then was that every witness's evidence on oath was true.<ref name="Turner421"/> Perjury by witnesses began to be punished before the end of the 15th century by the [[Star Chamber]].

The immunity enjoyed by witnesses began also to be whittled down or interfered with by the Parliament in England in 1540 with subornation of perjury<ref name="Turner421"/> and, in 1562, with perjury proper. The punishment for the offence then was in the nature of monetary penalty, recoverable in a civil action and not by penal sanction. In 1613, the Star Chamber declared perjury by a witness to be a punishable offence at common law.

Prior to the 1911 Act, perjury was governed by section 3 of the [[Maintenance and Embracery Act 1540]] 5 Eliz 1 c. 9 ({{lang|enm|italic=no|An Act for the Punyshement of suche persones as shall procure or comit any wyllful Perjurye}}; repealed 1967) and the [[Perjury Act 1728]].

=====Materiality=====

The requirement that the statement be material can be traced back to<ref>''[[Archbold Criminal Pleading, Evidence and Practice]]''. 1999. Paragraph 28-160 at page 2303. They cite 3 Inst 167.</ref> and has been credited to<ref>Smith, J. C, and Hogan, Brian. ''Criminal Law''. Sweet & Maxwell. 1965. Second Edition. Page 506.</ref> [[Edward Coke]], who said:

{{Blockquote|For if it be not material, then though it be false, yet it is no perjury, because it concerneth not the point in suit, and therefore in effect it is extra-judicial. Also this act giveth remedy to the party grieved, and if the deposition be not material, he cannot be grieved thereby.<ref>3 [[Institutes of the Lawes of England|Inst]] [https://archive.org/details/thirdpartinstit01cokegoog/page/n212 <!-- pg=166 --> 167]. This passage is quoted by Smith, J. C, and Hogan, Brian, ''Criminal Law'' (Sweet & Maxwell, 1965) (2nd Edition), p. 506.</ref>}}

====Northern Ireland====
Perjury is a statutory offence in [[Northern Ireland]]. It is created by [http://www.legislation.gov.uk/nisi/1979/1714/article/3 article 3(1)] of the [[Perjury (Northern Ireland) Order 1979]] (S.I. 1979/1714 (N.I. 19)). This replaces the [[Perjury Act (Northern Ireland) 1946]] (c. 13) (N.I.).

=== United States ===
{{See also|United States free speech exceptions}}

Perjury operates in American law as an inherited principle of the [[common law]] of England, which defined the act as the "willful and corrupt giving, upon a lawful oath, or in any form allowed by law to be substituted for an oath, in a judicial proceeding or course of justice, of a false testimony material to the issue or matter of inquiry".<ref>{{cite book|last=Clark|first=William|title=Hand-Book of Criminal Law|url=https://archive.org/details/handbookcrimina00clargoog|year=1894|publisher=West Publishing Company}}</ref>

[[William Blackstone]] touched on the subject in his ''[[Commentaries on the Laws of England]]'', establishing perjury as "a crime committed when a lawful oath is administered, in some judicial proceeding, to a person who swears willfully, absolutely, and falsely, in a matter material to the issue or point in question".<ref>{{cite book|last=Blackstone|first=William|title=Commentaries on the Law of England|url=https://archive.org/details/lawsofenglandc04blacuoft|year=1765|publisher=Oxford Printed at the Clarendon Press}}</ref> The punishment for perjury under the common law has varied from death to banishment and has included such grotesque penalties as severing the tongue of the perjurer.<ref name="Doyle 2010">{{cite journal|last=Doyle|first=Charles|title=Perjury Under Federal Law: A Brief Overview|journal=Congressional Research Service|year=2010|url=https://digital.library.unt.edu/ark:/67531/metadc287926/}}</ref> The definitional structure of perjury provides an important framework for legal proceedings, as the component parts of this definition have permeated jurisdictional lines, finding a home in American legal constructs. As such, the main tenets of perjury, including [[mens rea]], a lawful oath, occurring during a judicial proceeding, a false testimony have remained necessary pieces of perjury's definition in the United States.<ref>{{cite book|last=Livingston|first=Edward|title=A System of Penal Law for the United States of America|year=1828}}</ref>

====Statutory definitions====
Perjury's current position in the American legal system takes the form of state and federal statutes. Most notably, the United States Code prohibits perjury, which is defined in two senses for federal purposes as someone who:

{{Blockquote|(1) Having taken an oath before a competent tribunal, officer, or person, in any case in which a law of the United States authorizes an oath to be administered, that he will testify, declare, depose, or certify truly, or that any written testimony, declaration, deposition, or certificate by him subscribed, is true, willfully and contrary to such oath states or subscribes any material matter which he does not believe to be true; or
(2) in any declaration, certificate, verification, or statement under penalty of perjury as permitted under section 1746 of title 28, United States Code, willfully subscribes as true any material matter which he does not believe to be true<ref>{{cite book|title=United States Code, Title 18, Part 1, Section 1621}}</ref>}}

The above statute provides for a fine and/or up to five years in prison as punishment. Within federal jurisdiction, statements made in two broad categories of judicial proceedings may qualify as perjurious: 1) Federal official proceedings, and 2) Federal Court or Grand Jury proceedings. A third type of perjury entails the procurement of perjurious statements from another person.<ref name="Doyle 2010"/> More generally, the statement must occur in the "course of justice," but this definition leaves room open for interpretation.<ref name="Clark 1894">{{cite book|last=Clark|first=William|title=Hand-Book of Criminal Law|url=https://archive.org/details/handbookcrimina00clargoog|year=1894|publisher=West Publishing Co.}}</ref>

One particularly precarious aspect of the phrasing is that it entails knowledge of the accused person's perception of the truthful nature of events and not necessarily the actual truth of those events. It is important to note the distinction here, between giving a false statement under oath and merely misstating a fact accidentally, but the distinction can be especially difficult to discern in court of law.<ref>{{cite book|last=Shuy|first=Roger|title=The Language of Perjury Cases|year=2011|publisher=Oxford University Press}}</ref><ref>{{cite book |last1=Doyle |first1=Charles |title=False Statements and Perjury: An Overview of Federal Criminal Law |date=11 May 2018 |publisher=Congressional Research Service |location=Washington, DC |url=https://fas.org/sgp/crs/misc/98-808.pdf |access-date=2 December 2018 |archive-url=https://web.archive.org/web/20080605215046/https://fas.org/sgp/crs/misc/98-808.pdf |archive-date=5 June 2008 |url-status=dead }}</ref>

====Precedents====
The development of perjury law in the United States centers on ''United States v. Dunnigan'', a seminal case that set out the parameters of perjury within United States law. The court uses the Dunnigan-based legal standard to determine if an accused person: "testifying under oath or affirmation violates this section if she gives false testimony concerning a material matter with the willful intent to provide false testimony, rather than as a result of confusion, mistake, or faulty memory."<ref>{{cite book|title=United States v. Dunnigan 507 U.S. 87 (1993)}}</ref> However, a defendant shown to be [[Willful ignorance|willfully ignorant]] may in fact be eligible for perjury prosecution.<ref>{{cite book|title=United States v. Fawley (1998)}}</ref>

''Dunnigan'' distinction manifests its importance with regard to the relation between two component parts of perjury's definition: in willfully giving a false statement, a person must understand that she is giving a false statement to be considered a perjurer under the ''Dunnigan'' framework. Deliberation on the part of the defendant is required for a statement to constitute perjury.<ref name="cLARK 1894">{{cite book|last=cLARK|first=William|title=Hand-Book of Criminal Law|url=https://archive.org/details/handbookcrimina00clargoog|year=1894|publisher=West Publishing Co.}}</ref> Jurisprudential developments in the American law of perjury have revolved around the facilitation of "perjury prosecutions and thereby enhance the reliability of testimony before federal courts and grand juries".<ref>{{cite book|title=Dunn v. United States 480 U.S. 294 (1987)}}</ref>

With that goal in mind, Congress has sometimes expanded the grounds on which an individual may be prosecuted for perjury, with section 1623 of the United States Code recognizing the utterance of two mutually incompatible statements as grounds for perjury indictment even if neither can unequivocally be proven false.<ref>{{cite book|title=United States Code, Title 18, Part 1, Section 1623 (c)}}</ref> However, the two statements must be so mutually incompatible that at least one must necessarily be false; it is irrelevant whether the false statement can be specifically identified from among the two.<ref>{{cite book|title=United States v. McAfee 971 F.2d 755 (1992)}}</ref> It thus falls on the government to show that a defendant (a) knowingly made a (b) false (c) material statement (d) under oath (e) in a legal proceeding.<ref>{{cite book|title=United States v. Gorman}}</ref> The proceedings can be ancillary to normal court proceedings, and thus, even such menial interactions as bail hearings can qualify as protected proceedings under this statute.<ref>{{cite book|title=United States v. Greene 355 U.S. 184 (1957)}}</ref>

Wilfulness is an element of the offense. The mere existence of two mutually-exclusive factual statements is not sufficient to prove perjury; the prosecutor nonetheless has the duty to plead and prove that the statement was willfully made. Mere contradiction will not sustain the charge; there must be strong corroborative evidence of the contradiction.<ref>''People v Cash'', 388 Michigan Reports 153 (1972). See ''People v McIntire'', 232 Mich App 71 (1998), ''rev’d on other grounds'' 461 Mich 147 (1999).</ref>

One significant legal distinction lies in the specific realm of knowledge necessarily possessed by a defendant for her statements to be properly called perjury. Though the defendant must knowingly render a false statement in a legal proceeding or under federal jurisdiction, the defendant need not know that they are speaking under such conditions for the statement to constitute perjury.<ref>{{cite book|title=United States v. Yermian 468 U.S. 63 (1984)}}</ref> All tenets of perjury qualification persist: the "knowingly" aspect of telling the false statement simply does not apply to the defendant's knowledge about the person whose deception is intended.

====Materiality====
The evolution of United States perjury law has experienced the most debate with regards to the materiality requirement. Fundamentally, statements that are literally true cannot provide the basis for a perjury charge<ref>{{cite book|title=''Bronston v. United States'', 409 U.S. 352 (1973)}}</ref> (as they do not meet the falsehood requirement) just as answers to truly ambiguous statements cannot constitute perjury.<ref>{{cite book|title=''United States v. Richardson'', 418 U.S. 166 (1974)}}</ref> However, such fundamental truths of perjury law become muddled when discerning the materiality of a given statement and the way in which it was material to the given case. In ''United States v. Brown'', the court defined material statements as those with "a natural tendency to influence, or is capable of influencing, the decision of the decision-making body to be addressed," such as a jury or grand jury.<ref>{{cite book |title=''[[United States v. Brown]]'', 381 U.S. 437 (1965)}}</ref>

While courts have specifically made clear certain instances that have succeeded or failed to meet the nebulous threshold for materiality, the topic remains unresolved in large part, except in certain legal areas where intent manifests itself in an abundantly clear fashion, such as with the so-called [[perjury trap]], a specific situation in which a prosecutor calls a person to testify before a grand jury with the intent of drawing a perjurious statement from the person being questioned.<ref>{{cite journal|last=Gershman|first=Bennett|title=The "Perjury Trap"|journal=Pace Law Faculty Publications|year=1981}}</ref>

====Defense of recantation====
Despite a tendency of US perjury law toward broad prosecutory power under perjury statutes, American perjury law has afforded potential defendants a new form of defense not found in the British Common Law. This defense requires that an individual admit to making a perjurious statement during that same proceeding and recanting the statement.<ref>{{cite book|title=United States Code, Title 18, Part 1, Section 1623 (d)}}</ref> Though this defensive loophole slightly narrows the types of cases which may be prosecuted for perjury, the effect of this statutory defense is to promote a truthful retelling of facts by witnesses, thus helping to ensure the reliability of American court proceedings just as broadened perjury statutes aimed to do.

====Subornation of perjury====
Subornation of perjury stands as a subset of US perjury laws and prohibits an individual from inducing another to commit perjury.<ref>{{cite book|title=United States Code, Title 18, Part 1, Section 1622}}</ref> Subornation of perjury entails equivalent possible punishments as perjury on the federal level. The crime requires an extra level of satisfactory proof, as prosecutors must show not only that perjury occurred but also that the defendant positively induced said perjury. Furthermore, the inducing defendant must know that the suborned statement is a false, perjurious statement.<ref>{{cite book|title=Rosen v. N.L.R.B. 735 F.2d 564 (1984)}}</ref>