WASHINGTON — The political weapon cabinet might need restocking. “Liberal,” it appears, isn’t the lethal label it used to be.

It was a reliable bludgeon for more than three decades, and Republicans pulled it out again on the 2008 campaign trail. But in Colorado, Democrat Mark Udall won the race for U.S. Senate despite persistent GOP efforts to brand him “Boulder Liberal Mark Udall.”

And Barack Obama is president-elect, even with a National Journal listing that ranked him the Senate’s most liberal member.

In the face of those defeats, GOP strategists are questioning whether they’ve lost their favored tactic for the short term or forever. Democrats are watching young voters’ opinions. And those who track political language are listening for the next catchword.

“I suspect that the heyday of using ‘liberal’ as an attack word is over,” said George P. Lakoff, a University of California-Berkeley cognitive linguistics professor. “It has pretty much gone out of use, except by conservatives that are attacking people. ”

The meaning of “liberal” today veers far from its original definition. More than a century ago, it described proponents of individual liberty, free trade and free markets. In the years following President Franklin D. Roosevelt’s terms, Lakoff said, it signified support of government intervention. People proudly called themselves liberals.

“Liberal” became political poison in the early 1970s, during the presidential campaign of Republican Richard Nixon against Democrat George McGovern.

Republicans in that race used “liberal” to describe people they considered radical, opponents of the Vietnam War, and supporters of social change, including legalized abortion. It worked. Nixon won re-election over McGovern by a 23-point margin.

Republicans have used it in elections ever since.

Some argue it’s still relevant and that voters in 2008 picked personality over ideology.

“This whole election turned on the unpopularity of George Bush and the collapse of the economy and finally the charisma of Barack Obama,” said Dick Wadhams, campaign manager for Republican Bob Schaffer, who lost the Senate race to Udall. “There would be no other circumstance where a Boulder liberal could be elected to the U.S. Senate or a liberal like Barack Obama could be elected president of the United States.”

“Might never work again”

Udall “ran” from the “liberal” label, Wadhams said, proof that he knew Colorado voters reject liberal philosophies.

Udall aides said he wasn’t available for comment, but during the campaign, he said labels didn’t apply.

“It’s pretty hard to characterize me,” he said in an early 2008 interview. “I see myself as an independent Western Democrat.”

Former U.S. Sen. Ben Nighthorse Campbell, a Colorado Republican, called it a mistake to rely on the “liberal” label as a weapon in the Senate race.

“I don’t think it works anymore. It might never work again,” Campbell said. “People are trying to look beyond the labels. They want action. They want change. They want something to happen.”

And while “liberal” is seen as equal to “I take poison,” in some Western Slope communities, Campbell said, moderates and Republicans in Denver and the suburbs don’t recoil when someone says the word.

Despite failing to wound those at whom it was thrown this year, “liberal” still isn’t a positive word, said Robert Borosage, co-director of Campaign for America’s Future, which calls itself “the strategy center for the progressive movement.”

“It still polls more negative than positive when you ask people what you think of the word,” Borosage said.

Most voters don’t see themselves as liberal. When Pew Research Center for People and the Press asked people to describe their ideology this year, 38 percent called themselves conservative, 35 percent said moderate and 21 percent said liberal.

But Rep. Diana DeGette, a Denver Democrat, argues that “liberal” has lost some of its negative meaning.

“A generational shift”

“What you see in this election was really a generational shift,” DeGette said. Younger voters, she said, “don’t know about the negative connotations of ‘liberal’ because . . . the pejorative use of ‘liberal’ to mean big spending, morally lax, is just not true anymore.”

Younger voters are more friendly toward the “liberal” label.

In NBC News exit polls after a Feb. 5 Democratic primary vote, 58 percent of voters ages 17 to 29 described themselves as liberal. In the 30-to-44 age category, 51 percent said they were liberal.

But the word really didn’t work as epithet this year because the economy dominated as the issue voters cared about, Borosage said, and voters “turned against the conservative policies that had failed.”

“It just didn’t have the force it might have once had,” Borosage said.

Anne C. Mulkern: 202-662-8907 or amulkern@denverpost.com