The president, without any say from anyone else, can send the Marine Corps anywhere in the world to do anything he wants. That's why the Marines are often the first ones in a fighting zone, because they don't need an act of war to be present.
I wasn't talking about going into a foreign country. I was talking about turning on Americans. Re-read pjhoover53's post, then mine and you will see we didn't mention going into foreign countries. The topic was whether thery would turn on Americans in the Presidents ordered them to do so.
The President won't just arbitrarily decide to send troops on our own. He wil have to have a VERY good reason to send troops on our own. Also, I'm pretty sure it has to go through a couple people to prevent such an action. Checks and balances.
