The vitriolic “progressive” blogosphere may end up sinking the Democratic Party, as they launch vicious attacks against any Democrat who fails to embrace their wacko far-left agenda: Blogs Attack From Left as Democrats Reach for Center. (Hat tip: Carl.)

Democrats are getting an early glimpse of an intraparty rift that could complicate efforts to win back the White House: fiery liberals raising their voices on Web sites and in interest groups vs. elected officials trying to appeal to a much broader audience.

These activists — spearheaded by battle-ready bloggers and making their influence felt through relentless e-mail campaigns — have denounced what they regard as a flaccid Democratic response to the Supreme Court fight, President Bush’s upcoming State of the Union address and the Iraq war. In every case, they have portrayed party leaders as gutless sellouts.

First, liberal Web logs went after Democrats for selecting Virginia Gov. Timothy M. Kaine to deliver the response to Bush’s speech next Tuesday. Kaine’s political sins: He was too willing to drape his candidacy in references to religion and too unwilling to speak out aggressively against Bush on the Iraq war. Kaine has been lauded by party officials for finding a victory formula in Bush country by running on faith, values and fiscal discipline.

Many Web commentators wanted Rep. John P. Murtha (D-Pa.), a leading critic of the Iraq war who advocates a speedy withdrawal, to be the opposition voice on the State of the Union night. Most Democratic lawmakers have distanced themselves from the Murtha position. “What the hell are they thinking?” was the title of liberal blogger Arianna Huffington’s column blasting the Kaine selection.