Under pressure to support the troops but end the war, House Democrats said Thursday they would send President George W. Bush $50 billion for combat operations on the condition that he begin withdrawing troops from Iraq. The proposal, similar to one Bush vetoed earlier this year, would identify a goal of ending combat entirely by December 2008. It would require that troops spend as much time at home as they do in combat, as well as effectively ban harsh interrogation techniques like waterboarding. In a private caucus meeting, Pelosi told rank-and-file Democrats that the bill was their best shot at challenging Bush on the war. And if Bush rejected it, she said, she did not intend on sending him another war spending bill for the rest of the year. "This is not a blank check for the president," she said later at a Capitol Hill news conference. "This is providing funding for the troops limited to a particular purpose, for a short time frame."