Not stepping down.
Good, it would be like demanding that the biggest klutz get kicked off your opponents baseball team so they could replace him with someone that could actually play. I think they should be forced to keep Franken, it will only (if it's even possible) embarrass the Democrats further. The only downside is that they have no shame so they aren't too concerned as long as they are allowed to continue picking the pockets of oblivious taxpayers.
“Think of how stupid the average person is, and realize half of them are stupider than that.”
― George Carlin