I disagree that "You can't, so forget it."
The answer is for those of us with the longer view to ratchet up our disapproval of the NeverTrump and NeverCruz minorities. If either of these groups stays home in November, then Hillary wins.
I would like to believe that most of those two groups would, in fact, support the Republican in November over Hillary or Bernie. Certainly some will.
But their intranisigence now is costing us. If it is true that they would support Hillary over Cruz or Hillary over Trump, then I think they are in the wrong place and should have discussions with Bernie supporters on some other forum. As long as those people are here, then the focus of the rest of us should be to help them understand the stakes and get them to commit to keeping Hillary or Bernie out of the White House.
Is there anyone on this forum who believes that the Democrats are better off having Bernie challenging Clinton? With any luck they will each eventually destroy the other. We should learn from their experience and avoid that.
I'm not talking about people we can influence. If the convention cheats Trump and Cruz voters, millions of people who don't read FR or any other movement conservative site, those people will be mad as Hell. Some will come around and support whatever yellow dog is nominated, but millions won't. That's the inevitable result of screwing over your base. Selling that turd sandwich to GOP voters in November... good luck with that.
Combine the lost base with the fact that a candidate with relatively unified support - Romney - still lost in 2012 and we face an uphill battle. I'm a Trump guy in large part because he changes the map. He's playing an all new game.
No one else running can do that.