They're Expecting Trouble

One more step in the process of making sure that the totalitarians can clamp down on "civilian unrest." Foreign troops are a lot more likely to not identify with Americans who are not rolling over for a government takeover. American troops can hardly be regarded as reliable when it comes to arresting, shooting at, killing or imprisoning their fellow Americans. So the obvious solution is to get foreign troops in here to do the dirty work.
It is likely that we will see more of this, with troops of other nations, and the "United Nations" being stationed here just to keep order.