The NY Times editorial page, for once, nails it:
The defeat of Senator Joseph Lieberman at the hands of a little-known Connecticut businessman is bound to send a message to politicians of both parties that voters are angry and frustrated over the war in Iraq. The primary upset was not, however, a rebellion against the bipartisanship and centrism that Mr. Lieberman said he represented in the Senate. Instead, Connecticut Democrats were reacting to the way those concepts have been perverted by the Bush White House.
Ned Lamont, a relative political novice, said he ran against Mr. Lieberman because he was offended by the senator’s sunny descriptions of what was happening in Iraq and his denunciation of Democrats who criticized the administration’s handling of the war. Many other people in Connecticut may have felt that sense of frustration, but no one else had the money and moxie to do what Mr. Lamont did. Mr. Lieberman was stunned to find himself on the defensive, and it was only in the last few weeks that the 18-year veteran mounted a desperate campaign to reclaim his party’s support.
Senator Lieberman says he will run as an independent in November, taking on Mr. Lamont and the Republican, Alan Schlesinger. Mr. Schlesinger is a very weak candidate, but Mr. Lieberman should consider the risk of splitting his party if the Republicans are able to convince Mr. Schlesinger to drop out of the race in favor of a stronger nominee.
Mr. Lieberman’s supporters have tried to depict Mr. Lamont and his backers as wild-eyed radicals who want to punish the senator for working with Republicans and to force the Democratic Party into a disastrous turn toward extremism. It’s hard to imagine Connecticut, which likes to be called the Land of Steady Habits, as an encampment of left-wing isolationists, and it’s hard to imagine Mr. Lamont, who worked happily with the Republicans in Greenwich politics, leading that kind of revolution.
The rebellion against Mr. Lieberman was actually an uprising by that rare phenomenon, irate moderates. They are the voters who have been unnerved over the last few years as the country has seemed to be galloping in a deeply unmoderate direction. A war that began at the president’s choosing has degenerated into a desperate, bloody mess that has turned much of the world against the United States. The administration’s contempt for international agreements, Congressional prerogatives and the authority of the courts has undermined the rule of law abroad and at home.
Yet while all this has been happening, the political discussion in Washington has become a captive of the Bush agenda. Traditional beliefs like every person’s right to a day in court, or the conviction that America should not start wars it does not know how to win, wind up being portrayed as extreme. The middle becomes a place where senators struggle to get the president to volunteer to obey the law when the mood strikes him. Attempting to regain the real center becomes a radical alternative.