Editing Strategic Defense Initiative (section)

===National BMD===
The [[US Army]] considered the issue of ballistic missile defense (BMD) after [[World War II]]. Studies suggested that attacking a [[V-2 rocket]] would be difficult because the flight time was so short that it would leave little time to forward information through [[command and control]] networks to missile batteries. [[Bell Labs]] pointed out that although longer-range missiles flew much faster, their longer flight times would ease the timing issue and their high altitudes would ease long-range [[radar]] detection.{{sfn|Jayne|1969|p=29}}

This led to a series of projects including [[Nike Zeus]], [[Nike-X]], [[Sentinel program|Sentinel]] and ultimately the [[Safeguard Program]], all aimed at developing a system to defend against attacks by Soviet ICBMs. The programs proliferated because of the changing threat; the Soviets claimed to be producing missiles "like sausages", and ever-more missiles would be needed to defend against their fleet. Low-cost countermeasures such as [[penetration aids|radar decoys]] required additional interceptors. An early estimate suggested $20 spent on defense would be required for every $1 the Soviets spent on offense. The addition of [[Multiple independently targetable reentry vehicle|MIRV]] in the late 1960s further moved the balance in favor of offensive systems. This massively skewed [[cost-exchange ratio]] prompted observers to propose that an [[arms race]] was inevitable.{{sfn|Kent|2008|p=49}}

[[File:LIM-49A Spartan mockup.png|thumb|The [[Nike-X|Extended Range Nike Zeus]]/[[LIM-49A Spartan|Spartan missile]] of the late-1960s was designed to provide full-country defense as part of the Sentinel-[[Safeguard Program|Safeguard]] programs. Projected to cost $40&nbsp;billion (${{inflation|US|40|1966}} billion in {{currentyear}}) it would have offered minimal protection and damage prevention in an all-out attack.{{sfn|Ritter|2010|p=154}}]]

President [[Dwight D. Eisenhower]] asked [[DARPA|ARPA]] to consider alternative concepts. Their Project Defender studied many approaches before concentrating on [[Project BAMBI]]. BAMBI used satellites carrying interceptors that would attack the Soviet ICBMs upon launch. This [[boost phase]] intercept rendered MIRV impotent; a successful attack would destroy all of the warheads. Unfortunately, the operational cost of such a system was so large that the [[US Air Force]] rejected the concepts. Development was cancelled in 1963.<ref>{{cite web |website=Astronautix.com |url=http://www.astronautix.com/b/bambi.html |archive-url=https://web.archive.org/web/20161227220849/http://astronautix.com/b/bambi.html |url-status=dead |archive-date=December 27, 2016 |title=Bambi}}</ref><ref>{{cite news |url=https://www.nytimes.com/1986/10/28/science/star-wars-traced-to-eisenhower-era.html |newspaper=The New York Times |title='STAR WARS' Traced to Eisenhower Era |first= William |last= Broad |date=October 28, 1986}}</ref>

During this period, the entire topic of BMD became increasingly controversial. Early deployment plans were met with little interest, but by the late 1960s, public meetings on the Sentinel system were met by thousands of angry protesters.<ref name=today>{{cite web |first=Sharon |last=Watkins Lang |url=https://www.army.mil/article/142123/SMDC_History__Today_in_Space_and_Missile_Defense_History/ |title=Today in Space and Missile Defense History |date=February 3, 2015 |website=US Army}}</ref> After thirty years of effort, only one such system was built; a single base of the original Safeguard system became operational in April 1975, but was closed in February 1976.<ref>{{cite news
|title=Safeguard ABM System to Shut Down
|newspaper=The New York Times
|date=November 25, 1975
|author=John W. Finney
|url=https://www.nytimes.com/1975/11/25/archives/safeguard-abm-system-to-shut-down-5-billion-spent-in-6-years-since.html
|quote=the utility of Safeguard to protect Minuteman will be essentially nullified in the future}}</ref>

A Soviet military [[A-35 anti-ballistic missile system]] was deployed around Moscow to intercept enemy [[ballistic missile]]s targeting the city or its surrounding areas. The A-35 was the only Soviet ABM system allowed under the 1972 [[Anti-Ballistic Missile Treaty]]. In development since the 1960s and in operation from 1971<ref name=astro>{{cite encyclopedia |url=http://www.astronautix.com/lvs/a35.htm |title=A35 |encyclopedia=Encyclopedia Astronautica |access-date=June 7, 2007 |archive-url=https://web.archive.org/web/20070702003434/http://www.astronautix.com/lvs/a35.htm |archive-date=July 2, 2007 |url-status=dead }}</ref> until the 1990s, it featured the nuclear-tipped [[ABM-1 Galosh|A350]] [[exoatmospheric]] interceptor missile.