They're not.
According to polls, Trump's popularity has gone way down since his election. His support among his base hasn't changed; these people's identity is completely wrapped up in him and as far as they're concerned, he can do no wrong, but they're at most 30-32% of the electorate. Trump wouldn't have been elected with just those voters. He also enjoyed the support of other conservative Republicans who voted for him based on party affiliation and general agreement with his stated policies - reducing immigration, lowering prices, staying out of foreign wars, etc. It's these people who have become disillusioned over his blatant corruption and self-dealing, his gross incompetence, the Epstein files, starting the Iran war for no apparent reason (and losing it), and failing to address inflation.
Trump isn't on the ballot this November, but some Republicans have asked him to not campaign with them as this may do them more harm than good. The complete failure of Republicans in Congress to rein him in is leading some conservative voters to either support centrist Democrats when possible, or not vote at all due to lack of enthusiasm. I live in Georgia, which not long ago was a solid Republican state, but today Democrat Jon Ossoff is leading his Republican Senate challenger by double digits, and Democrat Keisha Lance Bottoms stands a good chance of being elected governor.
This pattern is being duplicated elsewhere, where Democrats are leading in swing states. Texas may elect its first Democratic Senator since Lloyd Bentsen in 1988, a year before James Talarico, the current Democratic candidate, was even born. Granted, part of this has to do with Talarico being a very gifted speaker, while his opponent, Ken Paxton, is a terrible candidate with a background of corruption and criminality, who may have been hurt more than he was helped by Trump's endorsement.
