Most Republican leaders appear to be horrified by President Trump’s comments about this weekend’s deadly white supremacist rally in Charlottesville, Virginia. But they have a problem: Their voters mostly agree with Trump. Two-thirds approve of Trump’s response to the Charlottesville attack, and of his description of who’s to blame.

What’s going on here?

There are two, probably mutually reinforcing explanations.

1. Like Trump, many Republican voters are increasingly sympathetic to a white supremacist worldview, and/or believe the true extremists are the leftist agitators who want to disrespect our national history.

2. Some Republican voters are looking to their party leader, President Trump, to explain and make sense of events for them, and if they approve of Trump (which most of them do), they’ll agree with what he says.

There’s a case to be made for both explanations.

Certainly, if Trump were entirely out of the mainstream of Republican opinion on these issues, he would never have won the nomination in the first place, given the overt racism he displayed in the primaries. So that’s a pretty strong case for point one. Moreover, as I found in my Democracy Fund Voter Study Group analysis of the 2016 elections, conservative views on race and identity now largely unify the Republican Party, whereas the party’s voters are much more divided on economic views.

But general predispositions aside, many Republican voters are also trying to figure out exactly how they should understand the events in Charlottesville, and they’re looking to their leaders for advice and guidance. Indeed, one of the most consistent findings for decades in political science is that voters look to leaders and party elites to help them make sense of events, and even to define what values they should prioritize as partisans.

The more Trump speaks out and explains to Republican voters how to interpret the events in Charlottesville (and whatever conflicts come next, as there will almost certainly be more), the more Republican voters will adapt to the new meaning of Republicanism.

The only way to prevent this from happening would be for Republican leaders who oppose this drift to speak much more forcibly and offer a strong condemnation, not only of the actions of white supremacist groups but of Trump’s defective moral compass. They need to show that you can be a Republican and stand on the side of folks standing up to white supremacists.

There are two reasons Republican leaders have not challenged Trump more forcibly.

One is that they fear Trump’s popularity, which remains high among Republican voters, still hovering around 80 to 85 percent.

Sen. Jeff Flake, who has most forcibly opposed Trump, is now suffering from an 18 percent approval rating in Arizona. Republican voters are also overwhelmingly siding with Trump in his recent tussle with Senate Majority Leader Mitch McConnell. This stands as an obvious warning to others who would challenge Trump.

Yet part of the reason for his high approval is that almost all Republican leaders publicly support Trump. So if you’re a Republican partisan, every signal you’re getting is: Republicans support Trump.

Thus, it’s a Catch-22: For Republicans to break with Trump, his popularity numbers would need to sink to the point where they could challenge him with some impunity. For his popularity to sink to that level, more Republicans would need to publicly break with Trump and signal that it’s okay to oppose Trump and still be a Republican in good standing. It’s possible there could be a cascade of Republicans turning on him, but as I argued in a recent piece, it’s still unlikely.

The second reason Republican leaders have been sticking with Trump publicly is that a major break with the president among leading Republicans would probably create an open civil war in the Republican Party, which would almost certainly spell electoral doom for Republicans in the near future. If Republicans split, Democrats win.

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?

This is a moment when Republican leaders might still be able to do something to fight against the full white supremacist takeover of Republican Party ideology, if they do so forcibly. But the longer they dither and vacillate, the more Trump continues to send clear signals without interference, and the harder it becomes to reverse course.

If they don’t act soon, the divide over foundational questions of American identity and heritage will become an even more unbridgeable chasm. And then we will have a national polity with no shared consensus about the meaning of that nation. If that sounds worrisome, remember the reason Robert E. Lee is a household name in the first place.