I'm not surprised to learn that most Democrats are uninterested in challenging President Obama for the Democratic nomination:
Dissatisfaction from some Democratic activists notwithstanding, 78 percent of Democrats approve of Obama, according to the latest Gallup survey. In particular, liberal Democrats and African Americans show strong support for the president, at 78 percent and 85 percent, respectively. Even with the president's concessions to conservative policies, he can still count on solid support from his base.
This makes for an interesting contrast to Bill Clinton. As Pew points out, by the end of his second year in office, 66 percent of Democrats and Democratic-leaning voters wanted to see Clinton challenged for the presidential nomination. To be fair, this poll was taken in December 1994, right after Republicans took the House, and not summer 1995. It's possible that Democrats would have been far less eager to challenge Clinton after a half-year of Republican radicalism.
Still, even after the large GOP gains of last year, there wasn't any sense that Democrats wanted to challenge Obama for the presidential nomination. As such, its worth looking at the differences between now and then. In addition to growing partisanship of the American electorate, my guess is that the contrast has a lot to do with the unique circumstances of the 1994 Republican takeover. Not only was Clinton less accomplished as a president – having met few of his goals by the election – but the Republican Revolution was a genuine shock to most Democrats, given the party's 40-year control of the House of Representatives.
By contrast, Obama entered the 2010 elections with an impressive set of accomplishments under his belt: universal health care, financial sector reform, hundreds of billions in new investment, and laws ensuring fair pay for women and equal protection for gays and lesbians. Democrats might have been shocked by the scale of the GOP's win – and unable to grasp its implications – but they weren’t disappointed with the president.