I'm not too worried about my fellow Democrats. While Clinton and Sanders supporters are passionate about their personal favorite, I think most of them realize that either one is a thousand times better than anyone the Republicans might nominate. I think they will come together in November to support the Democratic nominee.
I'm not at all sure the Republicans can do that.
It's looking likely that the GOP's nominee will be Donald Trump. The only person who can stop him at this point is Ted Cruz -- and Cruz would likely need an open convention to have a chance of doing that (a convention where no candidate can get a majority on the first ballot). And right now, the party is deeply split between those who support Trump and those who oppose Trump (and would like almost anyone else).
Trump is almost sure to get to the convention with more delegates than anyone else. And his supporters are the true-believers -- the teabaggers who have been pushing the party far too the right in the last few years. They haven't wanted their fellow Republicans to compromise on anything, and have been deeply disappointed in the candidates put forth in the last couple of elections by the GOP establishment. It is very likely that they will revolt if the party denies Trump the nomination. They will either stay home or vote for one of the minor right-wing parties (Libertarians, Constitution Party, etc.).
On the other hand, there are a lot of establishment Republicans who just cannot stomach having Trump as their candidate. They dislike him so much that they are starting to line up behind Ted Cruz (who they detest). And some polls have shown that as many as 20% to 30% of Republicans say they will not vote for Trump if he is nominated. They would vote Clinton, stay home, or leave the presidential slot on the ballot unmarked.
This is worrying the hell out of party leaders. They could lose significant votes if they nominate Trump, and could also lose significant votes if they don't nominate him.
Is there a way out of this mess for the Republicans? I doubt it. I just don't see the party coming together behind Trump, or someone else. What do you think?
NOTE -- The caricatures of Trump and Cruz above are by DonkeyHotey.)