[dragonwriter]

> US military officers swear an oath to defend the constitution against all enemies foreign and domestic,

True, but...

> but they don't swear an oath to other officers or elected officials.

... this part is, interestingly true, but only of officers. Officers don't swear an oath to other offices or elected officials, but enlisted personnel do both -- first to the President and second to the officers appointed over them, and all subject to the UCMJ. [0]

Not, of course, that oaths constrain behavior, but, to the extent oaths are relevant, in any case, the Constitution names the President Commander-in-Chief of the military and gives Congress the power to regulate the military, so an oath by a military member to support the Constitution necessarily involves a degree of commitment to elected officials, and to the extent those elected officials have used their Conditional powers to establish and appoint superior officers, those other officers.

[0] http://www.history.army.mil/html/faq/oaths.html

[anonymousguy]

Perhaps the necessary enough justification could be that an elected president does something that directly and literally violates an article written into the actual constitution and the military seeks to appoint a new leader from the line of succession. That way there is no violation of the principals of Cincinnatus and an elected civilian retains the position opposed to an unelected military figure.