Matt Yglesias points out a lag between reality and the political strategies favored by some self-styled “progressives”:
To accomplish the things I want to see accomplished, people who want change need to correctly identify the obstacles to change. If members of congress are replaced by less-liberal members in the midterms, then the prospects for changing the status quo will be diminished. By contrast, if members are replaced by more-liberal members (either via primaries or general elections) the prospects for changing the status will be improved. Back before the 2008 election, it would frequently happen that good bills passed congress and got vetoed by the president. Since Obama got elected, that doesn’t happen anymore. Now instead Obama proposes things that get watered down or killed in congress. That means focus needs to shift.