Republicans are cautiously optimistic the battle over a vacant Supreme Court seat will save the party’s Senate majority, hopeful the issue will convince disaffected, swing-state conservatives to reelect vulnerable GOP incumbents despite reservations about President Trump.

Senate Republicans have their backs against the wall in competitive battlegrounds — Arizona, Colorado, Iowa, and Maine — and states that typically vote GOP for president: Alaska, Georgia, Montana, North Carolina, and South Carolina. An open seat the party holds in Kansas is also in some peril. Losing just three could put Democrats in charge of the chamber beginning in January. But Republican strategists are comparing the unexpected Supreme Court confirmation fight to catastrophic insurance.