I have PreCheck and Clear. As such, I've regularly gotten to DCA 30 minutes before departure and been fine.

Last week, I had a 4 PM departure. I thought this would be a bit before the rush. Nope. PreCheck was winding around the rope line because DCA TSA is badly understaffed. (I don't know if TSA is trying to make a point to Congress, but I'd have thought they'd want their DCA operation to impress lawmakers.)

Anyway, TSA took 15 minutes, at which point I got to the gate with eleven minutes before departure—four minutes after the door closed. I begged and they let me on, only for the captain to complain to the gate agent for reopening the aircraft door to let me on (I was surprised too).

Now, I'm getting to DCA 50-60 minutes early like a normal human. At least until TSA staffs up.