Would Foreign Armies Benefit From An Invasion Of The U.S.?

After all this time of observing, I am happy to say that I think the U.S. military will not directly attack the American people. All people on all sides of every ocean know that, through the magic of technology, soldiers are as angry about our nonsensical wars as anyone else stateside.

History shows us the answer to this problem: hire foreign mercenaries to attack and put down the population for you. This tactic has been repeated many times because it is effective.

Some say it is the plan for putting down the U.S. population, as it becomes more and more clear that the military members here will not be willing to fire on one of their own, be they in Kansas or Kalamazoo.

My question for these foreign mercenary armies is,

Who is your real enemy?