Conservative commentators have long talked about "Islamo-fascism." Depicting the struggle as one against Islamic fascists is "an appropriate definition of the war that we're in," said GOP pollster Ed Goeas. "I think it's effective in that it definitively defines the enemy in a way that we can't because they're not in uniforms."

But Muslim groups have cried foul. Bush's use of the phrase "contributes to a rising level of hostility to Islam and the American-Muslim community," complained Parvez Ahmed, chairman of the Council on American-Islamic Relations.

"The 'war on terror' has always been a misnomer, because terrorism is an instrument, it's not an ideology. So I would always have preferred it to be called the 'war with radical Islam,' not with Islam but with 'radical Islam,'" Ross said.

Why even mention the religion? "Because that's who they are," Ross said. "Fascism had a certain definition. Whether they meet this or not, one thing is clear ... they represent a completely radical and intolerant interpretation of Islam."

While "fascism" once referred to rigid, nationalistic one-party dictatorship, it has "been used very loosely in all kinds of ways for a long time," said Wayne Fields, a specialist in presidential rhetoric at Washington University in St. Louis.

"Typically, the Bush administration finds its vocabulary someplace in the middle ground of popular culture. It seems to me that they're trying to find something that resonates, without any effort to really define what they mean," Fields said.

Pollster Andrew Kohut, director of the Pew Research Center, said the "fascist" label may evoke comparisons to World War II and remind Americans of the lack of personal freedoms in fundamentalist countries. "But this could only affect public opinion on the margins," he said.

"Having called these people 'evildoers,' fascism is just a new wrinkle," he said.