There are two conflicting stories that the progressive left is telling on the tax deal that Obama and Republicans made:
1) The Republicans were holding us hostage.
2) We could have gotten a better deal.
One of these must be false. If tax cuts for high-income Americans are unpopular, and Democrats could indeed have gotten more out of the GOP by forcing them to stand in the light next to the upper-class tax cuts, then Republicans were never really holding anyone hostage.
If, on the other hand, the Republican position was politically advantageous, and Democrats were faced with a disaster if they opposed, then yes, they were being coerced– vote for this thing you don’t like, otherwise you’re going to lose in 2012.
So which is true?
If anything, the truth is that Democrats could have gotten a better deal. Republicans, most notoriously John Boehner, were not at all willing to fight over the upper-income tax cuts. They said as much themselves. If Obama had really wanted to, he could have gotten tax cuts on the lower and middle class without having to give them to the upper class. Republicans were not ready to kill policies that both Republicans and Democrats support just for the hope of obtaining concessions– if you’d come to them with a yes-or-no vote on extending tax cuts on the lower tax brackets, you’d have seen a lot of yes votes.
But to think of things in terms of whether or not Democrats could have wheedled more concessions from Republicans on taxes is a little simplistic. Political compromise is not a zero-sum game, and there was a lot more in this deal than just the Bush tax cuts. Though in the electoral sense Republicans and Democrats do face a zero-sum game (for every seat you control, that is one less seat that I control), it is possible for both Democrats and Republicans to come out ahead, policy wise, by finding a middle ground. Had Democrats insisted on getting two policy points for every one that Republicans got, a lot less would have been agreed on and both sides would have fewer points total.
Some on the far left and far right have some very skewed policy preferences, and will see the pros of the deal outweighed by the concessions that were made. But to the political center, this looks like win-win.