No way, our government won't send so many troops because half of them will die while they are rather expensive. The US usually wages proxy wars, making other countries armies fight for American political and economic reasons. So forget about mass mobilization.
America's days of proxy wars are quickly becoming a thing of the past. I think Ukrainian President Poroshenko recently learned that his "friends" the Americans were feeding him a bunch of faulty intel. I think the Ukraine crisis is a lesson to the world just how far America will go to achieve what is in its interests. Our coalitions are no longer willing partners but members of nations which have agendas they are trying to advance through conflict.
So how far America will go? Ok, maybe far but not so fast, mostly waiting for something. And this war in Ukraine is still proxy too, there are no other countries citizens fighting, only locals and they fight for other countries reasons indeed.
There is no limit to how far America will go. In a couple other threads I gave reference to a discussion between someone and the previous director of the CIA. He said that the biggest change caused by the legislation passed after 911 regarding the CIA was that people in the field had to watch their back more than their front. In other words they now had to worry they might be answerable to someone. So what did the CIA do? Create a new shadow CIA, one that would not be answerable to anyone again. He said it with a wink but it was hardly a subtle wink, especially for the CIA. So how far will America go? Until it implodes.
And on the topic of ISIS, I noticed Russia offered Egypt help with ISIS.