The basic rules of Washington is to make yourself look better then everyone else, distort the other guys message, and never take responsibility unless people like what you're taking responsibility for. By admitting defeat in the coming election, Gibbs broke all those rules and managed to piss off the entire Democratic Party at the same time.
Give him some slack though, he's lasted a lot longer then some of his predecessors and when you're talking to the media every day you're bound to screw up at one point or another. Of course the reality (and what any political consultant in the district will tell you) is that the Democrats are going to lose seats in Congress this coming election, it is only a question of how many.
However, I don't believe it is as obvious or gloomy as Gibbs had stated it on Meet The Press. The problem with the Democrats messaging is that they have been on the defensive, always trying to explain what they are doing. This is especially dangerous when people are anxious and need help. But the fact is this Congress has done a lot of good. Between health care reform and the new Wall Street regulations they have accomplished a lot, and when people look back on it, they will be grateful this reforms were passed.
A recent poll conducted by the moderate think tank Third Way showed how bringing former President Bush back into the picture, voters are much more willing to vote for the Democrat.
David Broder wasn't so convinced. He thought the Republicans could just bring back Reagan since the same poll showed most people also wanted more tax cuts. But don't forget, this Congress gave 95% of Americas a tax cut and Reagan raised taxes in his first term.