WASHINGTON - "Some look at the challenges in Iraq and conclude that the war is lost and not worth another dime or another day," President Bush said recently.

Another time he said, "Some say that if you're Muslim you can't be free."

"There are some really decent people," the president said earlier this year, "who believe that the federal government ought to be the decider of health care ... for all people."

Of course, hardly anyone in mainstream political debate has made such assertions.

When the president starts a sentence with "some say" or offers up what "some in Washington" believe, as he is doing more often these days, a rhetorical retort almost assuredly follows.

The device usually is code for Democrats or other White House opponents. In describing what they advocate, Bush often omits an important nuance or substitutes an extreme stance that bears little resemblance to their actual position.

He typically then says he "strongly disagrees" - conveniently knocking down a straw man of his own making.

Bush routinely is criticized for dressing up events with a too-rosy glow. But experts in political speech say the straw man device, in which the president makes himself appear entirely reasonable by contrast to supposed "critics," is just as problematic.

Because the "some" often go unnamed, Bush can argue that his statements are true in an era of blogs and talk radio. Even so, "'some' suggests a number much larger than is actually out there," said Kathleen Hall Jamieson, director of the Annenberg Public Policy Center at the University of Pennsylvania.

A specialist in presidential rhetoric, Wayne Fields of Washington University in St. Louis, views it as "a bizarre kind of double talk" that abuses the rules of legitimate discussion.

"It's such a phenomenal hole in the national debate that you can have arguments with nonexistent people," Fields said. "All politicians try to get away with this to a certain extent. What's striking here is how much this administration rests on a foundation of this kind of stuff."

Bush has caricatured the other side for years, trying to tilt legislative debates in his favor or score election-season points with voters.

Not long after taking office in 2001, Bush pushed for a new education testing law and began portraying skeptics as opposed to holding schools accountable.

The chief opposition, however, had nothing to do with the merits of measuring performance, but rather the cost and intrusiveness of the proposal.

Campaigning for Republican candidates in the 2002 midterm elections, the president sought to use the congressional debate over a new Homeland Security Department against Democrats.

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 of Arizona.

Straw men have made more frequent appearances in recent months, often on national security - 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."