But Warner also knows: The Iraqi government's writ barely runs beyond Baghdad's Green Zone. The security forces are not yet competent to hold areas that U.S. forces clear of insurgents. Holding such areas might require sending more U.S. forces to Iraq, which would further alienate Iraqis. Moqtada al-Sadr, whose support helped make Nouri al-Maliki Iraq's prime minister, has a militia that is becoming Iraq's Hezbollah -- a sovereign force within the state, and one imperfectly controlled by Sadr.

For three reasons, Eisenhower's challenge in ending the Korean War was simpler than Bush's problem would be in extracting U.S. forces from Iraq: Eisenhower had a static military front. The U.S. objective of pushing the invaders from South Korea had been accomplished. And Eisenhower had a coercive threat.

In "The Cold War: A New History," John Lewis Gaddis of Yale, who calls Eisenhower "at once the most subtle and brutal strategist of the nuclear age," says that Eisenhower early in his presidency believed -- he later changed his mind -- that when nuclear weapons "can be used on strictly military targets and for strictly military purposes," they should be used "exactly as you would use a bullet or anything else." And Eisenhower allowed America's adversaries to know that his military advisers were seeking ways to use such weapons to end the Korean fighting.

Warner believes that most congressional Democrats understand that there is an unpopular way to oppose an unpopular war -- by voting for abandonment of all the objectives for which blood has been shed. Warner defines the U.S. objective in Iraq not in terms of a glittering achievement, democracy, but as avoiding something appalling -- the Iraqi oil fields in jihadists' hands. Regarding Iraq, there will not soon be an Eisenhower moment.