I think the problem is that if everybody shows up, 21 votes are required...
I don't think so. It's a simple majority of the quorum. Otherwise, why would they be requesting that some just walk off the floor?
They are hoping one walks off the floor without voting. A woman congress critter was supposed to do just that last time. But she got ticked off at some women praying outside of her office, so she voted no. Sounds like she's a real pushover...hopefully JJ got to her.