Well, ya know who does have a duty to support the constitution? Literally everyone in the military.
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. So help me God. - Oath of Enlistment
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; 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. So help me God. - Oath of Commissioned Officers
Notice that they both specify “all enemies, foreign and domestic”.
Every service member that’s had the opportunity to engage Trump the same way they do any other enemy to US, and chosen not to do so, has violated their oath.