http://www.opednews.com/articles/2/genera_by_dr__r_070913_duty_2c_honor_2c_country.htm

An Open Letter to the New Generation of Military Officers Serving and Protecting Our Nation
By Dr. Robert M. Bowman, Lt. Col., USAF, ret., National Commander, The Patriots

Excerpt:

"Our oath of office is to "protect and defend the Constitution of the United States against all enemies, foreign and domestic." Might I suggest that this includes a rogue president and vice-president? Certainly we are bound to carry out the legal orders of our superiors. But the Uniform Code of Military Justice (UCMJ) which binds all of us enshrines the Nuremberg Principles which this country established after World War II (which you are too young to remember). One of those Nuremberg Principles says that we in the military have not only the right, but also the DUTY to refuse an illegal order. It was on this basis that we executed Nazi officers who were "only carrying out their orders."