Republican leaders continue to let Trump turn the GOP into the white supremacist party

Lee Drutman wrote about how Trump is redefining GOP party values and why no one is stopping him for Vox's Polyarchy.

Of course, if the US had a multi-party system like most modern democracies, socially moderate Republicans would long ago have formed their own party, giving a pivotal share of the electorate an identity that would allow them to be socially moderate but fiscally conservative, like the old liberal Republicans who used to thrive in the North. But the US has winner-take-all elections, which give us only two parties. So once-moderate Republicans have over the decades either become Democrats and given up their economic conservatism or given up their social moderation in order to advance their economic conservatism. As a result, the center has fallen out of American politics, and racial divisions have consumed partisan divisions.

It may be too late at this point for more socially tolerant Republican leaders to bring the party back from the brink. They’ve had their chance for years, including before Trump, and they never took it. If anything, they encouraged it.

Now Trump is president. He’s the leader of the Republican Party, and he commands tremendous media attention and a very powerful platform. And he’s using it to define what it means to be a Republican, slowly but surely, with each press conference he gives and each tweet he sends.
I have no great insight into the deep psychology of Republican Party leaders, other than the overly simplistic but still predictive political science chestnut of treating them as single-minded seekers of reelection. But at some point, the obvious question becomes: Reelected to what? To be a member of the party of white supremacy? To hold office in a country torn apart by race war because they were too pusillanimous to stand up against the causes precipitating it?