West Virginia – Open (D): It's not that often that every elections analyst in the country concurs on something, but I suspect you will get unanimous agreement that this seat is far and away the most likely Senate seat to flip. Joe Manchin is a Democrat who has basically been swimming against a Republican tide since he won the seat in a 2010 special election. Two years prior, John McCain carried the state by 12 points over Barack Obama. Donald Trump won it by almost 40 points in 2020. It's unlikely that even the popular Manchin, who won narrowly in the good Democratic year of 2018, could emerge victorious, but with his retirement, the seat is just gone.

Montana – Jon Tester (D): Reasonable minds can disagree about whether Montana or Ohio is the more vulnerable seat. Tester is probably a better ideological match for his state than Sen. Sherrod Brown is for Ohio, but Montana will probably go for Donald Trump by 20 points rather than the 10 or so points by which he seems likely to carry Ohio. Tester's preferred opponent, Matt Rosendale, dropped out of the race, giving Tester a more mainstream opponent. Even Rosendale had made a race out of it in the bad GOP year of 2018, but this time, Tester will likely have to convince one out of every six Trump voters to cross over for him. That's no easy task.

Ohio – Sherrod Brown (D): Brown is probably too liberal for the modern Buckeye State, and he'll have to convince around one in 10 Trump voters to split their tickets. This is within tolerance – Susan Collins pulled this off in reverse in 2020 – but it is still rare. Brown only won by seven points against an underfunded opponent in 2018, but whoever the GOP candidate is will probably not have to worry about money. Trump endorsed businessman Bernie Moreno, much to the state GOP's dismay, but this is a state that voted for a similarly untested, controversial candidate in 2022 over Brown's political heir. Brown can win, but he's in trouble.