[2] I, [name], do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter.
It was first updated in September 1776, after the Declaration of Independence, to swear to be "true to the United States of America, and to serve them honestly and faithfully against all their enemies opposers whatsoever; and to observe and obey the orders of the Continental Congress and the orders of the Generals and officers set over me by them".
At this point, the reference to "them" was replaced with "it" to reflect the realities of the divided nation during the American Civil War, as well as the shifting attitude of viewing the United States as one entity rather than a collection of smaller ones.
[5] In 1868, the officer oath was simplified to: I, A.B., do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter.
[6]The enlisted oath underwent further revision and, as of 1862, read: : I, ___, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; and that I will obey the orders of the president of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice.