WASHINGTON, Nov. 19 — Former Secretary of State Henry A. Kissinger, who regularly advises President Bush on Iraq, said today that a full military victory was no longer possible there. He thus joined a growing number of leading conservatives openly challenging the administration’s conduct of the war and positive forecasts for it.

“If you mean, by ‘military victory,’ an Iraqi government that can be established and whose writ runs across the whole country, that gets the civil war under control and sectarian violence under control in a time period that the political processes of the democracies will support, I don’t believe that is possible,” Mr. Kissinger told BBC News.

In Washington, a leading Republican supporter of the war, Senator John McCain of Arizona, said American troops in Iraq were “fighting and dying for a failed policy.”

But Mr. McCain continued to argue vigorously for a short-term surge in American forces, and he gained a vocal ally in Senator Lindsey Graham of South Carolina, another influential Republican, who said, “We’re going to lose this war if we don’t adjust quickly.”