Elizabeth Bumiller, writing in the NYT (Jan. 25, 2004):

Historically, Americans have not voted out the commander in chief in the middle of war, which helps explain, Democrats say, why Mr. Bush used the grand stage of the State of the Union speech to underline the threat. ("And it is tempting to believe that the danger is behind us. That hope is understandable, comforting and false.") It is also why the president traced the two-year narrative of a war on terror and then rebutted those who questioned, as he put it, "if America is really in a war."

Historians say that Franklin D. Roosevelt would probably not have won a third term in 1940 had there not been the crisis in Europe and Hitler's invasion of France that June. "There were forces on the right who didn't like anything about the New Deal, he had not brought about economic recovery and a lot of people thought he had too much power," Mr. Kennedy said. "There's very little question he owes his third term, and his fourth as well, to the international crisis."

Similarly, in the Civil War election of 1864, Abraham Lincoln survived a challenge by George B. McClellan, the Democratic nominee and the general Lincoln had fired the year before. But it might have been otherwise had not General Sherman captured Atlanta two months before the election, turning Lincoln's fortunes around after a summer of devastating casualties. "Lincoln was elected on a tide of military success," said James M. McPherson, the Civil War historian. "But Lincoln and everybody else acknowledged that if the election had been held in August, it would have gone the other way."

Of course, unpopular wars have driven some presidents from office, like Lyndon B. Johnson, who chose not to run for re-election in 1968 because of his vulnerabilities over Vietnam. Harry S. Truman was so unpopular in 1952 because of the stalemate in Korea that he might not have won his party's nomination.

It is no surprise that the biggest fear of the current White House, short of another terrorist attack, is that Iraq will implode before the election. Barring that, political analysts say Mr. Bush is wise to wield his most powerful advantage against the opposition. In a New York Times/CBS News poll conducted just before the State of the Union, 68 percent, including majorities of both Democrats and independents, gave Mr. Bush high marks for the campaign against terrorism.