Ron Brownstein: “President Joe Biden won a decisive Electoral College victory in 2020 by restoring old Democratic advantages in the Rust Belt while establishing new beachheads in the Sun Belt.” “But this year, his position in polls has weakened on both fronts. The result is that, even this far from Election Day, signs are developing that Biden could face a last-mile problem in the Electoral College.” “Even a modest recovery in Biden’s current support could put him in position to win states worth 255 Electoral College votes, strategists in both parties agree.