The establishment's Trump delusion
This is certainly counter to the polling that shows Ted Cruz doing better in a head to head race with Democrats than Trump. Cruz also has a higher approval rating while Trump has higher negatives. I suspect their real concern is that Cruz will call their bluff on issues they claim they support.
Representative Charlie Dent, Republican of Pennsylvania, who has not made an endorsement, said that Mr. Trump could appeal to a wider bloc in the general election than Mr. Cruz.