If you`re talking about a military coup, we`ve been very careful to keep the military away from politics. Also, the top several layers of the military hierarchy are made up of civilian appointees, not General Officers. Also, Generals have no control over how soldiers are paid. That comes from all the way at the top in the DOD, so Generals can`t hand out fat bonuses to his troops to make them more loyal to him. Fortunately for us, an apolitical military is something deeply ingrained in our culture. If an active duty General started making public, inflamatory political statements, most Americans would feel queezy about it, even if they agreed with what he had to say. American political leaders have generally been quick to sack Generals who get too uppity, as well. Truman fired MacArthur when he started to buck, and even Obama sacked Stanley McCrystal over a bad Rolling Stone article.