Here’s the political reality for Senate Democrats: If they didn’t hold seats in states that Trump won by double-digit margins, Republicans would have 57 senators in the upper chamber—not far from a filibuster-proof majority. The five red-state Democrats up for reelection this year are absolutely critical to the party’s ability to win back control of the Senate in 2020 and beyond. If Democrats hold most of these red-state seats this year, they would have a decisive advantage taking back control of the Senate for the next two election cycles. Lose your most valuable members in 2018, however, and Republicans can plausibly talk about a long-term Senate majority.

The timing of Kennedy’s retirement couldn’t have come at a worse time for these embattled red-state Democrats. If Republicans remain united, Democrats won’t be able to do anything to prevent Trump’s nominee from getting confirmed. Three Democratic senators—Indiana’s Joe Donnelly, West Virginia’s Joe Manchin, and North Dakota’s Heidi Heitkamp—supported Neil Gorsuch’s confirmation last year and are likely to do the same for Trump’s second pick. Sens. Claire McCaskill of Missouri and Jon Tester of Montana voted against Gorsuch, but they will be under more pressure to support the new nominee since the timing of the vote is so close to the election. Sen. Doug Jones of Alabama, who isn’t up for reelection until 2020, wasn’t in the Senate for the Gorsuch confirmation fight.