It was supposed to be the GOP. The Republicans were supposed to tear themselves apart thanks to a brutal primary, an unpopular candidate the base wouldn't support, disorganization, and intra-party strife. It's still not impossible. There's a long time between now and the convention, so I suppose it could still happen. However, with each passing day, it looks like things are settling down on the right side of the election.
Across the aisle, however, chaos reigns.