On August 30, 2007, the Washington Post ran an article on how outrage over Congress's inability to stop Bush's abuses of power is splitting the Democratic Party from it's more liberal members. The article starts out by focusing on an ad that the ACLU is running which depicts Senate Majority Leader Harry Reid and House Speaker Nancy Pelosi as sheep. It goes on to explore the anger that the ad represents in more detail.
Not suprisingly, the split is between those Democrats who have to run in more conservative states and districts and activist groups who don't have such restrictions. This is always the problem with a party built around coalitions. The coalitions can be split. The Southern Democrat/Northeast Democratic split started in FDR's time and continues to this day. The question is whether the Democratic party activists will continue to work for the defeat of Republicans or whether at least some of them will take a "pox on both your houses" approach.