What will it take for Republicans to turn on Trump?

Lee Drutman wrote for Polyarchy on Vox  about why Republicans might not impeach Trump. 

For now, the “these emails are a big deal” voices among the Republicans are the usual Trump critics. John McCain. Lindsey Graham. Susan Collins. Their criticism tells us little.

What will be more telling is if and when other Republicans who have not yet been outspoken start to be. What will be telling is if and when Fox News and Breitbart take this story more seriously. What will be telling is if weeks go by and Ryan and McConnell fail to offer any defense of the Trump administration. Once a cascade begins, it tends to snowball.

If Republicans can’t get their act together to pass the Obamacare repeal bill they’ve promised to pass for going on eight years now, one wonders whether some in the party will start to wonder what the point of having a majority is anyway. If the health care bill fails to come together, and the Trump Jr. email story leads to bigger and more damning stories, the political calculus will begin to change. At that point, a genuine cascade will become more likely.