The threat of the Democrats loosing the majority in the Senate (again) is not so much the loss of opportunities to push thru a Democratic agenda -- that wasn't happening even with a supermajority of 60 because Obama felt the urge to fellate John Boehner instead of moving ahead with righting the wrongs from the Bush era. It certainly isn't happening with "only" a 9 seat majority, because you can easily write off at least nine of those Dems as sufficiently treasonous to the principles of the Democratic Party platform that they'd rather retire than get things done (viz. Evan Bayh retiring to spend more time with the millions that await him in his future life as a lobbyist for the same companies to which he catered as a cash-and-carry politician).

No, the threat is that even with the thinnest majority the GOP will be able to push thru their neanderthal agenda -- they have the ironclad party discipline to kick ass when given the chance, and on the few occasions when that fails them they can always count of a Lieberman or a Ben Nelson to screw the pooch and vote with the waterboarders in Congress...

So, no the dismay is not over all the good that could have been done -- that was never going to happen while Harry Reid drove his busful of misfits and miscreants around the countryside like some drunk frat boy on a joy ride, while Obama just watched like a traffic cop on 'ludes -- it's over the harm that is about to be done.