I swear that if I ever catch some guy in the act of lowering one of my country's flags and replacing it with a Mexican flag, I'm going to go get my .44 and shoot his ass.
I do solemnly swear 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 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. So help me God.
Took that oath when I enlisted. Doesn't seem to have an experiation date on it...