I understand the concern that a party only concerned with protecting its incumbents can end up becoming very insulated, but at the same I don't think it's a bad thing that to protect your own members, even in deep blue districts where there's no risk of losing the seat, either. For one thing, it cuts across both ways -- while it was frustrating that Pelosi backed Cuellar, it was good that she also backed Rashida Tlaib! That's a frustrating headwind when you're trying to get in through the door, but once you're in, that's a valuable source of support to have at your back.
But the other thing about that is, Congress isn't a legislating AI; its a body that works based on personal relationships forged between members, and when you've worked with someone on really challenging shit for years or decades, and they've supported your bills and you've supported theirs, is it that surprising or even necessarily bad that those people will tend to back incumbents? Look at how AOC endorsed Bush in 2018 but stayed silent in 2020 because she and Clay work together on a committee. Some might spin that as AOC already being compromised by the machine, but I think it's just the reality of, in Congress, power is derived from relationships, and endorsing one of your colleagues' primary challengers is kind of a big betrayal that will only hurt that relationship and, by extension, your own ability to get things done. And in this particular case, it's not as if Clay was some centrist Blue Dog; he was an advocate of the Green New Deal and M4A, so he is ideologically aligned with the left wing as it is (that said, I think his role in his state's gerrymander 10 years ago is alone worth his ouster).
In any event, listening to your constituents and acting on their behalf ultimately comes down to the person who represents that district and their challenger(s). Who are Pelosi or AOC or whomever to say what is or isn't in the best interests of the constituents of a district they don't live in, much less represent? Their endorsements are who about they want to work with, not who is the most effective spokesperson for a district that isn't their own. That ultimately comes down to the voters and is why guys like Crowley, Engel, Capuano, and Clay were all voted out.
He's powerless and it's driving him crazy and probably, in his own way, depressed.
poll.qu.edu
