Even if Trump comes up a little short of 1237, I think it will be so-close that it will be “a gimme”. Any maneuvering at the convention at that point will cause an ugly backlash. I can see that and I voted for Cruz in the Pennsylvania primary. If Cruz doesn’t win convincingly in Indiana after putting all his chips there, he HAS to concede IMO and support Trump. To do anything else courts disaster.
He’s already over a thousand.
Add in 51 from NJ and he needs about 180.
Leading in Indiana, Leading in CA.
If he does win tuesday, especially with a significant delegate count, there will be enough available in CA alone to put him over the top.
Add in WV and NM where he is likely to gain significant delegates, and this is all but over.
It’s a math game at this point, and the challengers cannot win through their performance with voters.