If we stick with only what we know, it remains conventional to believe, for instance, that Senator Ted Cruz will win reelection in red Texas—the political handicappers don’t view him as highly vulnerable—but it’s not implausible to believe, in a blue-wave year, that his challenger, Beto O’Rourke, who’s outraising Cruz in the money chase, and who was within the margin of error in a recent poll, could shock us all when the votes are tallied.

If we stick with only what we know, we’ll focus mostly on the House—which seems poised to flip because Democrats are strong in districts dominated by college-educated suburbanites. As the conservative political analyst Henry Olsen said the other day, “We’re not talking about whether or not the Democrats are going to do extremely well. We know Democrats are going to do extremely well.” By contrast, the Senate will be largely contested in the rural and small-town red states where Trump scored solid wins in 2016; Democrats have the misfortune of defending 10 Senate seats on Trump turf. And Trump is betting, not without reason, that most voters in those states will be galvanized by his pet themes: race and culture.

He knows that GOP control of the Senate is crucial not just to his agenda, but to his survival. If Democrats win the chamber, they would snuff his ongoing mission to appoint conservatives to the federal judiciary. And if Democrats win the House and move on impeachment, presumably with evidence amassed by Mueller’s team, Trump wants to ensure that the Senate won’t have the votes to convict—or the power to conduct new investigations.

So, with help from his media friends, he’s pushing the hottest button of all. On air yesterday, the Fox News host Laura Ingraham, a stalwart ally, framed the stakes for Trump voters: “The America we know and love doesn’t exist anymore. Massive demographic changes have been foisted on the American people, and they are changes that none of us ever voted for, and most of us don’t like … This is related to both illegal and legal immigration."

Ingraham was swiftly assailed for peddling white nationalism—the conservative commentator S. E. Cupp tweeted at her: “Speak for yourself, and every other last gasp of a dying gen … WE love this country’s diversity”—but, her visceral rhetoric aside, what’s arguably most noteworthy is her targeting of legal immigration. This appears to be a new front for the Trump-allied forces, as also evidenced by a pending White House plan to revoke the resident status of legal immigrants who enroll in federal-aid programs—such as food stamps and public housing—to which they are currently entitled.

Until now, they were only targeting undocumented immigrants; now they’ve expanded their ambitions. The broad theme—which they hope will resonate in the key red-state Senate contests—is that Trump and his Republican candidates are strong on keeping all immigrants at bay, and that the Democrats are weak. And the strategy might work; according to a June poll conducted by the Pew Research Center, a plurality of Republicans nationwide cite immigration as their top issue of 2018.