They do not think he can beat Hillary. In fact, the Republicans’ private polling suggests he would have a devastating effect on down ballot races at both the federal and state level. Having just seen the largest shift to the GOP since the late 1800’s, every single data point that they would normally read suggests Republican insiders should be doing everything imaginable to stop him.
But instead of stopping Trump, a growing number of Republican insiders are starting to think he would be a better nominee than Ted Cruz. The reason, however, is not what you are thinking.
Republican insiders in Washington, above all else, want to preserve their status quo. They want to make sure they do not lose power, access to power, privileges ordinary Americans do not have, etc. And they know with Donald Trump, one of two things will happen.
Either Trump will lose to Hillary Clinton, as their data objectively suggests, or Trump will win and can be negotiated with as he forms a coalition to govern. A coalition to govern would necessarily, in their minds, mean them.
With Cruz, one of two things will happen. Either Cruz will win, and there is a good chance he would, or Cruz would lose. If Cruz lost, they would have Hillary Clinton to work with, they know her and do not dislike her. If Cruz won, the man who puts principle above raw politics who they desperately hate might dare reshape the Republican Party.
The men and women whose livelihood depends on the status quo cannot let that happen.
Republicans in Washington often claim that conservatives like to take their football and go home when their candidate does not win. The evidence for that is sparse. More often than not, it is the Republican establishment that bolts when they lose. In number defeats in the past four years, the losing Republican establishment was willing to side with Democrats.
In this 2016 election, despite the future of the Supreme Court being on the line, Republican leaders in Washington are vastly more interested in self-preservation than national preservation. In their minds, that means backing Trump over Cruz.