The source of frustration for an over-extended primary campaign season should not be Senator Clinton. Every candidate has every right to run and it is expecting far too much of a campaign to pack it up when victory is still possible -- particularly when she lost so narrowly.
But there is no excuse for superdelegates to remain neutral. In fact, there is no such thing. At some point, every superdelegate must choose, transforming the neutral superdelegate into every other kind of delegate: lined up with one of the candidates. By the time of the actual vote on the floor of the convention in Denver, there will be no neutral superdelegates. They will either be voting for Senator Obama or Senator Clinton. The fiction of the neutral superdelegate is the raison d'etre of the Clinton campaign. If there are neutral superdelegates, then Hillary can convince them to vote for her up until the very last moment. If there are not any neutral delegates to win over, however, then there is no longer any reason to campaign as the contest has been lost.
Thus, calling on Senator Clinton to quit misses the point. Howard Dean got it right, as did Tennessee Governor Phil Bredsen: superdelegates must choose, sooner rather than later, and in June at the latest. As P. Diddy might say, Choose or Lose.
Rahm Emanuel (my former Congressman) is a good example. He is one of about 300 "neutral" superdelegates. His decision to cling to neutrality is the fuel behind the continuing Clinton campaign. His decision has consequences and pressure should be brought to bear on him, not really on Senator Clinton.
Besides, it is a little unseemly to call on the candidate to drop out. I happen to think the damage done by another six weeks or so of campaigning is a bit oversold. I do think a campaign in June or July makes absolutely no sense, since at that point, all of the electorate has had a chance to speak and by that moment, every superdelegate no longer has any justification to cling to the fiction of neutrality. The more we put pressure on superdelegates to choose now, the more likely we are to support the move to create an overwhelming consensus that every superdelegate must choose or lose in June.