The reason Republicans let a non-issue like Mexican immigration destroy their party is racism.

Sean Trende, the wise, conservative-leaning election analyst for RealClearPolitics, acknowledges something most other conservatives will not.

Indeed, it’s common to hear Republicans and conservatives claim the opposite. Even Kevin Williamson, in his now-infamous riot-act reading to white Donald Trump supporters, conceded against reality that “current immigration levels” are “excessive and problematic.”

There are a couple things at work here. First, Republicans are near-pathologically unwilling to level with voters about a range of issues. Easier to channel outrage, biases, and suspicions, than challenge conservatives to make political decisions on factual merits. In that way, immigration denialism exemplifies my old point that critics are sanitizing Trumpism as “economic anxiety” when racism is a huge part of it. If labor competition alone explained Trumpism, Trumpism would be on the wane. Second, amid the Trump phenomenon, conservatives are beset by a desire to attribute his rise to external factors beyond their control. If illegal immigration is surging, it makes sense that working class voters are turning to Trump. If Obama is indifferent to or encourages immigration, Trump is partly his fault.

I imagine many Republicans wish they could take a mulligan—go back in time, pass comprehensive immigration reform, claim victory at the border. But now they’re stuck with this, probably until the next presidential election post-mortem.