It's a simple concept. At any speech or other appearance by any federal politician, Democrat or Republican (or media or corporate personality, same difference), who hasn't taken an unambiguous stand against war and for civil liberties (which is practically all of them, you can count the exceptions on one hand), turn your back the whole time.
This is a simple, low risk way to demonstrate contempt. It's not even sufficiently disruptive to justify police repression (though I'm sure they'll still think of some excuse). But if enough of us did this, it would sure get to these pricks. None of them is that thickskinned, in fact they are all fucking narcissists, or they wouldn't be in a job hovering in front of cameras all day.
They can rig the elections and sick the cops on us, but it still won't look too good attacking people from behind...
(Note: this tactic should be used against any political appointee of the current US federal gov without exception. Anyone who takes a job or orders of any kind from torturers and war criminals deserves no less.)