Today, there are 52 Republicans sitting in marginal districts with Cook PVI scores of R+5 or more Democratic more than twice the number Democrats need. The problem for Democrats is that these tend to be personally popular members: three quarters of them won their 2016 races by double digits, and half of them won by more than 15 points. For the most part, they know how to navigate tough districts and attract independent voters.
Of the 52, just four have announced retirements so far: Reps. Ileana Ros-Lehtinen (FL-27), Dave Trott (MI-11), Charlie Dent (PA-15) and Dave Reichert (WA-08). Their retirements have vaulted these seats to the top of Democrats' takeover list. But as the holidays near and retirement season looms, Democrats' chances hinge on how many of the other 48 stick around.