Citing the need to pass an extension of Bush-era tax cuts, vulnerable incumbent Sen. Michael Bennet (D-Colo.) voted against Senate adjournment Wednesday.

Endangered Sen. Blanche Lincoln also voted against the adjournment resolution that calls for the chamber to return for a lame-duck session Nov. 15, but it was not immediately clear why the Arkansas Democrat did so.

Despite the two Democratic defections, the adjournment resolution passed the Senate by a vote of 54-39. Most Republicans, save for New Hampshire Sen. Judd Gregg, voted against adjourning.

In a statement, Bennet said Senate leaders “should have brought the extension of key tax cuts to the floor for up or down votes. Both parties have played political games with the extension of the Bush tax cuts and with the estate tax. It’s past time for that to come to an end.”

Notably, however, Bennet said he wanted Senate Majority Leader Harry Reid (D-Nev.) to bring up a one-year extension of all Bush administration tax cuts, rather than the original Democratic plan to extend the cuts only for the first $250,000 in income for couples ($200,000 for individuals).

“When we return, I will support a one-year extension of all tax cuts and will fight for a long-term extension of middle class tax cuts,” Bennet’s statement said. “I have said for weeks that I would support a compromise that moves tax cuts forward. I have laid down a concrete proposal and will work with any Democrat or Republican who is willing to move forward in a productive way to get this done.”

Senate Democrats have been deeply divided during the past few weeks over whether to hold a vote on extending the 2001 and 2003 tax cuts. Most liberals wanted to vote on President Barack Obama’s plan to extend only “middle-class” tax cuts, while vulnerable incumbents like Bennet and Lincoln wanted to vote on their proposed compromise plans or not at all, several Democratic sources said.

With different factions of the party at an impasse over whether to compromise on the issue, Reid made the decision to forgo a vote until after the elections. Some Senators said the move was made in deference to vulnerable incumbents, such as Bennet and Lincoln, who did not want to vote on the president’s plan.

Senators and Democratic aides have argued that postponing the vote allows candidates to tailor their message to their state, rather than holding a vote that could be used against them in political ads.

Bennet also cited the need to pass the Defense Department authorization in explaining his vote against adjournment.