You know those movies where the frightened campers realize far too late they must work together to escape the grizzly? Yea, that’s pretty much the Republicans right now, and this week the biggest bruin, Donald Trump, could effectively polish off the last of them – which leads my three things to watch in politics.

1) LAIR OF THE SWAMP BEAR: Tuesday is last stand time for Marco Rubio in Florida – heck, maybe for the Republican Party as we know it. Just a few months ago Rubio thought his home state primary might clinch the nomination for him. Instead he is desperately trying to avoid a mauling by Trump on his own patio. At stake: 99 winner-take-all delegates. If Rubio snags them he’ll still be in a distant third place, but at least he’d have done his part to repel Trump’s charge. On the other hand, if Rubio loses on his own turf, the screams for him to drop out will be enough to make a politico’s blood run cold.

2) BUCKEYE BEAR: If Florida can’t do the job, maybe Ohio can. Governor John Kasich represents the second hope on Tuesday for the Republican establishment to stop Trump. Kasich is far down in the delegate count, but if he can collect Ohio’s 66 winner-take-all delegates that too could slow Trump’s rush to secure the nomination. Ted Cruz, btw, already burned his powder in his home state of Texas. He may be able to rack up more delegates, but if Trump takes a big enough bite on Tuesday, the math says the man from New York may be unstoppable.

3) BEARING UP: And what about the Democrats? Like one of those apocryphal stories Scout masters tell Webelos, Hillary Clinton has taken a pickaxe handle to Bernie Sanders over and over and he just keeps coming. Sanders’ Michigan surprise left Camp Clinton reeling, and all that talk of inevitability is gone – especially if you look at just the pledged delegates. It doesn’t help that she is still wrestling with email issues, and the Dem base is jittery about her strength. She will keep trying to turn the attention on her potential Republican opponent this week, but Sanders is showing sharper claws every day and she dare not turn her back on him, or he may shred her tent and make off with her cooler.

(CNN’s Tom Foreman is the author of “My Year of Running Dangerously” – which involves no bears.)