He told at least two audiences that some senators opposing him were "not interested in the security of the American people." In reality, Democrats balked not at creating the department, which Bush himself first opposed, but at letting agency workers go without the usual civil service protections.

Running for re-election against Sen. John Kerry in 2004, Bush frequently used some version of this line to paint his Democratic opponent as weaker in the fight against terrorism: "My opponent and others believe this matter is a matter of intelligence and law enforcement."

The assertion was called a mischaracterization of Kerry's views even by a Republican, Sen. John McCain (news, bio, voting record) of Arizona.

Straw men have made more frequent appearances in recent months, often on national security ¡ª once Bush's strong suit with the public but at the center of some of his difficulties today. Under fire for a domestic eavesdropping program, a ports-management deal and the rising violence in Iraq, Bush now sees his approval ratings hovering around the lowest of his presidency.

Said Jamieson, "You would expect people to do that as they feel more threatened."

Last fall, the rhetorical tool became popular with Bush when the debate heated up over when troops would return from Iraq. "Some say perhaps we ought to just pull out of Iraq," he told GOP supporters in October, echoing similar lines from other speeches. "That is foolhardy policy."

Yet even the speediest plan, as advocated by only a few Democrats, suggested not an immediate drawdown, but one over six months. Most Democrats were not even arguing for a specific troop withdrawal timetable.

Recently defending his decision to allow the National Security Agency to monitor without subpoenas the international communications of Americans suspected of terrorist ties, Bush has suggested that those who question the program underestimate the terrorist threat.

"There's some in America who say, 'Well, this can't be true there are still people willing to attack,'" Bush said during a January visit to the NSA.

The president has relied on straw men, too, on the topics of taxes and trade, issues he hopes will work against Democrats in this fall's congressional elections.

Usually without targeting Democrats specifically, Bush has suggested they are big-spenders who want to raise taxes, because most oppose extending some of his earlier tax cuts, and protectionists who do not want to open global markets to American goods, when most oppose free-trade deals that lack protections for labor and the environment.

"Some people believe the answer to this problem is to wall off our economy from the world," he said this month in India, talking about the migration of U.S. jobs overseas. "I strongly disagree."