Trump won in New Hampshire and has been polling strong in South Carolina, which is next. Kasich is a surprise second. Cruz is still in there and probably gets to run for a while on his Iowa win. But Rubio? If he stays at fifth it’s hard to see where he’s going from here. After all, he was only third in Iowa and that was supposed to catapult him up, not into a blunder and a further back finish. I don’t imagine Jeb is going away right now either, even though he hasn’t done well anywhere.
I think the short answer is: it’s on to South Carolina. Maybe Carson and Fiorina drop out, but it will probably be well into March until the GOP field is down to a two person race and by then Trump may have gained enough of a lead to make him hard to stop.
Not much of a surprise on the Dem side. If Bernie can’t convert that win into progress in South Carolina and Nevada, people will lose interest. If he does, there’s no telling when this one will be over. Maybe even after the Republicans, who at least have a frontrunner.