Bern it up with Sanders or burn it down with Trump

[6andcounting]

Someone who is new to politics and doesn't really have an ideology might be able to switch between Trump and Bernie just on the anti-establishment factor. Outside of promoting American economic protectionism, they don't have much else in common. Bernie supporters who despise Hilary just won't in an election between Trump and Clinton. That still helps Trump because it's one less vote for Hillary, but it will only be a net gain of +1 not +2 for Trump.

The better and longer Bernie performs in the primary, the more likely his supporters who are otherwise Democrat voters just sit out when Hilary's nominated. However, Trump is getting votes from people who normally don't vote, or at least not for republicans. Some republicans don't like him, but he certainly has energized the base. Cruz supporters are still going to end up voting for Trump because of his energy and pure dislike for Hillary and the Obama policies she will continue. Bernie is bringing the energy for the left, so when he drops out so does their energy. About as many people are truly thrilled and excited to vote for Hillary as Jeb Bush, and 95% of those people are just caught up in the fact that she has (semi-safe assumption) a vag.