Editing Albert Sidney Johnston (section)

==United States Army==
[[File:AlbertSJohnston.jpg|thumb|Johnston as commander of the Department of Utah. Portrait taken by [[Samuel C. Mills]] at [[Camp Floyd]], Utah Territory, winter of 1858–59]]
When the United States declared war on Mexico in May 1846, Johnston rode 400 miles from his home in [[Galveston, Texas|Galveston]] to [[Port Isabel, Texas|Port Isabel]] to volunteer for service in Brigadier General [[Zachary Taylor]]'s Army of Occupation. Johnston was elected as [[Colonel (United States)|colonel]] of the 1st Texas Rifle Volunteers but the enlistments of his soldiers ran out just before the army's advance on [[Monterrey]], so Taylor appointed him as the inspector general of Brigadier General [[William Orlando Butler|William O. Butler's]] division of volunteers. Johnston convinced a few volunteers of his former regiment to stay on and fight.

During the [[Battle of Monterrey]], Butler was wounded and carried to the rear, and Johnston assumed an active leadership role in the division. Future U.S. general, [[Joseph Hooker]], was with Johnston at Monterrey and wrote: "It was through [Johnston's] agency, mainly, that our division was saved from a cruel slaughter... The coolness and magnificent presence [that he] displayed on this field... left an impression on my mind that I have never forgotten."<ref name=":0">Roland, pp. 243</ref> General Taylor considered Johnston "the best soldier he had ever commanded."<ref>{{Cite book |last=Taylor |first=Richard |title=Destruction and Reconstruction: Personal Experiences of the Late War. |publisher=Appleton and Company |year=1879 |location=New York |pages=232}}</ref>

Johnston resigned from the army just after the battle of Monterrey in October 1846. He had promised his wife, Eliza, that he would only volunteer for six months' service. In addition, President [[James K. Polk]]'s administration's preference for officers associated with the Democratic Party prevented the promotion of those, such as Johnston, who were perceived as Whigs:

{{blockquote| Authorized to appoint a large number of officers in the increased military force, raised directly by the United States, an unjust discrimination was made in favor of Democrats... Not one Whig was included, and not one of the Democratic appointees had seen service in the field, or possessed the slightest pretension to military education. Such able graduates of West Point as [[Henry Clay Jr.|Henry Clay, jun.]], and William R. McKee, were compelled to seek service through State appointments in volunteer regiments, while Albert Sidney Johnston, subsequently proved to be one of the ablest commanders ever sent from the Military Academy, could not obtain a commission from the General Government. In the war between Mexico and Texas, by which the latter had secured its independence, Johnston had held high command, and was perhaps the best equipped soldier, both by education and service, to be found in the entire country outside the regular army at the time of the Mexican war. General Taylor urged the President to give Johnston command of one of the ten new regiments. Johnston took no part in politics; but his eminent brother, [[Josiah S. Johnston|Josiah Stoddard Johnston]], long a senator from Louisiana, was Mr. Clay's most intimate friend in public life, and General Taylor's letter was not even answered.<ref name=Blaine>[http://www.gutenberg.org/cache/epub/21128/pg21128.html Blaine, James Gillespie, ''Twenty Years of Congress'', Vol. 1, Ch. 4.]</ref>}}

He remained on his plantation after the war until he was appointed by later 12th president [[Zachary Taylor]] to the [[United States Army|U.S. Army]] as a [[Major (United States)|major]] and was made a paymaster in December 1849 for a district of Texas encompassing the military posts from the upper Colorado River to the upper Trinity River.<ref name=EB1911/> He served in that role for more than five years, making six tours and traveling more than {{convert|4000|mi|km}} annually on the Indian frontier of Texas. He served on the Texas frontier at [[Fort Mason (Texas)|Fort Mason]] and elsewhere in the western United States.

In 1855, 14th president [[Franklin Pierce]] appointed him colonel of the new 2nd U.S. Cavalry (the unit that preceded the modern [[5th Cavalry Regiment (United States)|5th U.S.]]), a new regiment, which he organized, his lieutenant colonel being Robert E. Lee, and his majors [[William J. Hardee]] and [[George Henry Thomas|George H. Thomas]].<ref name=EB1911/> Other subordinates in this unit included [[Earl Van Dorn]], [[Edmund Kirby Smith]], [[Nathan George Evans|Nathan G. Evans]], [[Innis N. Palmer]], [[George Stoneman]], R.W. Johnson, [[John Bell Hood|John B. Hood]], and [[Charles W. Field]], all future Civil War generals.<ref>Johnston, pp. 185</ref> On March 31, 1856, Johnston received a promotion to temporary command of the entire Department of Texas. He campaigned aggressively against the [[Comanche]], writing to his daughter that "the Indians harass our frontiers and the 2nd Cavalry and other troops thrash them wherever they catch them."<ref>{{Cite journal |last=Shaw |first=Arthur M. |date=1942 |title=Albert Sidney Johnston in Texas: Letters to Relatives in Kentucky, 1847–1860 |journal=Register of the Kentucky State Historical Society  |volume=40 |issue=132 |pages=290–317}}</ref> In March 1857, Brigadier General [[David E. Twiggs]] was appointed permanent commander of the department and Johnston returned to his position as colonel of the 2nd Cavalry.