Arizona Sen. John McCain had no kind words for President Donald Trump yesterday when he lambasted him for his press conference with Russian President Vladimir Putin in Helsinki, Finland.

Accusing Trump of favoring Putin at the expense of the U.S.’ NATO allies, the 81-year-old senator denounced the meeting as “one of the most disgraceful performances by an American president in memory.”

McCain asserted, “President Trump proved not only unable, but unwilling, to stand up to Putin. He and Putin seemed to be speaking from the same script as the president made a conscious choice to defend a tyrant against the fair questions of a free press, and to grant Putin an uncontested platform to spew propaganda and lies to the world.”

Some Democrats are hoping that being denounced by a right-wing Republican war hawk and a Vietnam veteran such as McCain will harm Trump’s popularity with his hardcore supporters, but that probably won’t happen. To Trumpistas and the alt-right, McCain is a “cuckservative” rather than a real conservative (“cuckservative” is the alt-right’s favorite insult for conservatives they believe aren’t right-wing enough). And Trump followers are unlikely to be swayed a bit by any criticism coming from McCain or neocon and Weekly Standard founder Bill Kristol—who has also criticized Trump for being more favorable to Putin than NATO.

Trump’s hardcore supporters are true believers. They connect with the president on purely a gut level and love how he says things as much as what he’s actually saying. To the alt-right, Trump is their guy—and Democrats would do well to understand that going into the 2018 midterms because that’s the level of passion they’re up against.

Trump hasn’t had very high approval ratings with the overall U.S. population, but among his hardcore followers, the president’s approval numbers are high—and that includes white evangelicals. A poll conducted by the Public Religion Research Institute in March found Trump’s support among white evangelicals to be 75%. People who have that favorable an opinion of him are likely to be bringing a great deal of passion with them when they go to the polls in November.

Of course, anti-Trump sentiment is quite vehement among liberals and progressives—who dislike Trump as passionately as his hardcore followers adore him. And the Democratic Party is going to need to tap into that passion in the November midterms.

However, disliking Trump is not enough for Democrats. Instead of merely articulating what they’re against, they will also need to articulate what they are for—and the Democrats who are driving passion this year include some who are running for office and some who are already in office, such as Bernie Sanders and Elizabeth Warren in the U.S. Senate. Much has been written about the enthusiasm surrounding 28-year-old Sanders ally Alexandria Ocasio-Cortez, who is running against Republican Anthony Pappas in Queens and the Bronx for a seat in the House of Representatives—and in Pennsylvania, Sanders has also been campaigning for Braddock Mayor John Fetterman, who is running for lieutenant governor and will be on a ticket with Gov. Tom Wolf in November.

Fetterman (who has been campaigning on things like universal health care, a $15 per hour federal minimum wage, legalizing marijuana and green energy) brings considerable energy to that race, and Democrats will need all the energy they can get in an important swing state like Pennsylvania—where Trump enjoys a lot of support in places like Altoona, Hollidaysburg and Johnstown even though he is wildly unpopular in Democrat-dominated Philadelphia. In fact, struggling Rust Belt locations like Altoona and Johnstown are where one finds some of the most ardent Trump supporters. And Wolf is going to need a strong turnout in Philadelphia and Pittsburgh in November in order to be reelected—especially if Trump is campaigning for his opponent in the central part of the state.

Earlier this year, Trump’s approval ratings peaked at 45% in Gallup’s tracking poll before falling to 42%. But that’s the general population; among Republicans, his approval ratings have been—according to Gallup—hovering around 90%. And Trump’s true believers are unlikely to lose their enthusiasm no matter how vehemently McCain criticizes the president.