I think there are two fracture points that will make 2028 a bad year for the united right. Epstein and Israel. If the files are ever substantially released you could see mass shifts in votes this midterm, and a fracture of establishment Republicans and new wave Republicans riding on them being too young to be in the files.
Israel is the next breaking point, as the general public turns against Israel as a state, the blackmailed and bought politicians will be stuck in a sinking ship and farther right politicians will swoop in against them. Voters may also just vote third party instead of a bought out AIPAC politician.
They fight It, end up in the sewer, realize if they lose their innocence It will lose interest in them, run the train, flashforward.
At least that’s what I remember from when I read the book without knowledge of that scene.