I didn't mind it when Lieberman ran in 2000, so it would be pretty hypocritical of me to oppose it in Biden's case.

But, to address Freestylah's point, if politicians weren't permitted to hold on to the offices they currently hold while seeking higher office, the choice of candidates would be even more dismal than it is now, since nobody would want to risk their current seat.

This would only serve to further entrench the lifers in Congress and grind what little progress there is to a halt.