It’s hard to recall a moment when Senate Republicans were more at odds with Donald Trump, whose all-consuming obsession with the SAVE America Act—his strict voter ID and proof-of-citizenship bill—has paralyzed Congress and pitted G.O.P. lawmakers against one another just months before the midterms. Senate majority leader John Thune has told the president on numerous occasions that he doesn’t have the votes for the bill, nor does he have the votes to eliminate the filibuster. And yet Trump wants what he wants: In the last few weeks, he’s canceled the signing of a bipartisan bill to lower housing costs; refused to sign a reauthorization of FISA Section 702, the critical international surveillance tool; sidelined Jay Clayton, his own nominee to replace Tulsi Gabbard as director of national intelligence; and vowed to withhold his endorsement from any lawmaker who doesn’t back the SAVE Act.