Incidentally, I actually agree that impeachment proceedings would be a Bad Idea (though I think the media should discuss the prospect of impeachment a whole lot), but what exactly is Megan talking about here?
Impeaching either the president or the vice president will take up all the time of the Congress for the next six months. That means not getting things done that presumably most of my progressive friends would like to see. It also means not having any achievements to show the electorate next year except . . . impeaching Bush.
Exactly how does Megan think Congress is working now? The Democrats were elected on one of the clearest agendas in modern times: Drawing down the Iraq War, passing anti-corruption legislation, and instituting a series of popular, if small, pieces of economic populism (increase in the minimum wage, Medicare bargaining, etc). Bush has stymied every one. And because Democrats don't have 60+ votes in the Senate, literally nothing has gone through. He has, in every way, used his control of the executive branch to thwart the clear will of the electorate. To say that he shouldn't be impeached because, well, that would keep Congress from actually getting things done is truly off-base.