House Speaker Paul Ryan is not a big fan of Donald Trump — that much is clear. He refused to back Trump during the Republican primaries and then held out on endorsing him even after Trump became the presumptive nominee. But eventually, Ryan did get behind Trump. And now, even after video of Trump bragging about being able to commit sexual assault has come to light, Ryan said he won’t defend Trump, but he has refused to unendorse the GOP nominee. Trump responded by attacking Ryan on Twitter.

A reasonable person might ask why, if Ryan was reluctant to support Trump to begin with, the speaker of the House isn’t washing his hands of the whole Trump campaign.

But the answer is simple: Republican voters like Trump; Ryan risks losing the support of rank-and-file GOPers if he hits Trump too hard.