In an interview Eric Foner is asked if he thinks the Republican Party is likely to break up

Which is more likely now: A short-lived break-away party, an organized effort to keep Trump from becoming the Republican nominee, or a Trump nomination and party takeover?

The thing is, putting together coalitions of dissidents is not all that easy. You notice that all these Republicans keep saying we have to stop Trump, but no one is willing to step aside, to fall in line and do what's necessary to unite the opposition behind one alternative.

I'm a historian, so I don't like predictions; they aren't my game. But I would say that history tells us that it's often not the voting that determines the election. It's whether or not an important or big part of your base is alienated.

With or without a third party, if a big portion of either party's voters just stay home, that's a bigger problem. And that is certainly possible if Trump is nominated. But unfortunately for the Republican Party, that's also true if Trump is not the nominee or somehow someone else is. I think that's also a situation where voters have in the past stayed home, where you could expect that people galvanized by Trump and his campaign would just stay home, making a Republican win unlikely too.

Interestingly, this is a year where that really could be an issue for both parties -- the Republicans and Democrats. We'll have to watch and see what happens in the coming months. But, I think there is some talk and some belief that something similar could happen with Sanders's voters if Clinton is the nominee.

I don't know that that is a situation we've seen before in both parties at the same time. Then, when you add to that the fact that in the 19th Century people were far more likely to vote a straight-party ticket and ballots were structured accordingly, there are also some very unpredictable things that could happen in November. In the 20th Century and certainly the 21st Century, that's far less common. So, I wouldn't be completely surprised if a number of people show up, cast no vote for president, but cast a vote for their [congressional] district seat. ...