Most of the signers are liberal Democrats, Politico.com reported. They include such prominent liberals as Maxine Waters of California, Barney Frank and Ed Markey of Massachusetts, John Lewis of Georgia and Jerrold Nadler of New York.
The pledge could cause problems for Majority Leader Nancy Pelosi, D-Calif. Earlier this year, many liberals agreed, reluctantly, to vote for Iraq appropriations bills.
"We are writing to inform you that we will only support appropriating additional funds for U.S. military operations in Iraq during Fiscal Year 2008 and beyond for the protection and safe redeployment of all our troops out of Iraq before you leave office," the letter began.
The group ended by saying that they agree "with a clear and growing majority of Americans" who no longer support an open-ended war.