NEW YORK — When President Barack Obama's re-election campaign unveiled its new slogan, some conservative critics were quick to pounce.

"Forward," they asserted, is a word long associated with Europe's radical left. Its choice reaffirmed their contention that Obama is, to some degree or other, a socialist – a claim that surfaced early in the 2008 campaign and has persisted ever since, fueling a lively industry of bumper stickers and books..

"New Obama slogan has long ties to Marxism, socialism," read a headline in The Washington Times. A column by Russian immigrant Svetlana Kunin, for Investor's Business Daily, said Obama seeks to move America forward to "total government involvement in people's lives."

This is far from a new phenomenon – the use of "socialist" as a political epithet in the U.S. dates back to pre-Civil War days when abolitionist newspaper editor Horace Greeley was branded a socialist by some pro-slavery adversaries. In the 20th century, many elements of Franklin Roosevelt's New Deal – including Social Security – were denounced as socialist. So was Medicare when it was created in the 1960s.

But to many historians and political scientists – and to actual socialists as well – the persistent claim that Obama is a socialist lacks credence.

He's widely seen as a pragmatist within the Democratic Party mainstream who's had ample success raising campaign funds from wealthy Wall Street capitalists. Even some of his strongest critics acknowledge that his administration hasn't sought one of the classic forms of socialism – government control of the nation's means of production.

Terence Ball, a political scientist at Arizona State University, said "socialist' has gained currency as an anti-Obama slur because "the `L' word (liberal) has lost it shock value."

"I grow weary of Obama and the Democrats being called socialist," said Ball, who has written about ideologies. "If you talk to any real socialist, they disown them very, very quickly."

Full-fledged U.S. socialists are relatively scarce these days – three socialist-oriented presidential candidates received about 21,000 votes among them in 2008. And current socialist leaders don't share the right-wing view that Obama is a fellow traveler.

"It makes absolutely no sense," said Greg Pason, national secretary of the Socialist Party USA. Obama's health care overhaul "is anything but socialist. It's bailing out for-profit companies."

Yet Pason has been pleased by the "socialist" rhetoric.

"We've had an opportunity to talk to people, and that's been a blessing," he said. "People have actually researched socialist organizations."

One tidbit they might learn: The Pledge of Allegiance – the epitome of American patriotism – was written in 1892 by a socialist clergyman, Francis Bellamy.

When the 2012 Republican presidential campaign was still competitive, three of the leading candidates – Rick Perry, Newt Gingrich and Michele Bachmann – depicted Obama as a socialist. Mitt Romney, the eventual winner, declined to go that far.

"I don't use the word `socialist,' or I haven't so far," Romney told CNN in an interview last year. "But I do agree that the president's approach is government-heavy, government-intensive, and it's not working."

In one of the GOP debates, Romney asserted that Obama "takes his political inspiration from Europe, from the socialist-democrats in Europe."

Radio host Rush Limbaugh was among several conservatives who chided Romney for his reluctance to call Obama a socialist outright.

"You know, I keep forgetting, the fact that Obama is black, is why we can't call him a socialist," Limbaugh said on one of his shows. "That had slipped my mind because when I look at Obama, I don't see black. I see a socialist. I see a Marxist."

A slew of books have been written by conservative authors trying to out Obama as socialist. Among the more ambitious, in terms of research, was "Radical in Chief" by Stanley Kurtz, a senior fellow at the Ethics and Public Policy Center, a conservative Washington think tank. Delving into Obama's years as a student and a community organizer, Kurtz contended that Obama is part of a coterie of "stealth socialists."

"Over the long term, Obama's plans are designed to ensnare the country in a new socialism, a stealth socialism that masquerades as a traditional sense of fair play, a soft but pernicious socialism similar to that currently strangling the economies of Europe," Kurtz wrote.

In much of today's world, socialism lacks the contentious overtones that it has in America.

The new French president, Francois Hollande, is a Socialist, and most of Western Europe adheres to socialist-style policies that endure under a variety of governing parties.

Canada, which resembles the U.S. in so many ways, has a universal health care system and its main opposition party, the New Democrats, is union-backed and has socialist roots.

One of the few contemporary U.S. politicians to embrace the socialist label is Sen. Bernie Sanders of Vermont. He formally lists himself as an independent, but throughout his career – including stints as a mayor and House member – he's described himself as a democratic socialist.

"Branding someone as a socialist has become the slur du jour by leading lights of the American right from Newt Gingrich to Rush Limbaugh," Sanders said in 2009. "If we could get beyond such nonsense, I think this country could use a good debate about what goes on here compared to places with a long social-democratic tradition like Sweden, Norway and Finland, where, by and large, the middle class has a far higher standard of living than we do."

The roots of socialism in America can be traced to the arrival of German immigrants in the 1850s, according to Rutgers University professor Norman Markowitz, who teaches the history of socialism and communism.

The Socialist Party of America grew significantly in the early 20th century under the leadership of union organizer Eugene V. Debs, electing a congressman and dozens of mayors. Debs ran for president five times, getting more than 913,000 votes in 1920 – the party's high-water mark. (At the time, Debs was in prison on charges that he had urged resistance to the draft during World War I.)

The party's following eroded during the 1920s, and Debs was succeeded as leader by Norman Thomas, a Presbyterian minister in New York. During the Great Depression, Thomas received 892,000 votes in the 1932 presidential election as Franklin Roosevelt won the first of his four victories.

After World War II, the anti-communist crusade led by Sen. Joseph McCarthy and the broader tensions of the Cold War relegated organized socialism in the U.S. to the political margins. The term "creeping socialism" emerged, used by conservatives to denigrate various policy proposals and initiatives that involved a role for the government.

After the Cold War's end, use of "socialist" as a political insult also receded. Markowitz believes its recent revival relates directly to the animosity toward Obama that is shared by a certain segment of Americans.

"There's this hysterical outbreak of abuse to prove that the president is not American, that he's a secret Muslim, that policies that past Republican administrations would have adopted are part of a socialist, communist conspiracy," Markowitz said.

Due in part to the multiple definitions of socialism, some conservatives wrestle with semantics as they seek appropriate terms for Obama's ideology.

"Instinctively, the president is a collectivist," said Ken Blackwell, former Ohio secretary of state and now a conservative commentator. "My fundamental belief is that he wants to transform our market economy into a government-controlled economy – not far afield from European-style socialism."

Steven Hayward, a resident scholar at the American Enterprise Institute and author of a two-volume biography of Ronald Reagan, said Obama is not a socialist under the strict definitions of that term – central economic planning and government control of production.

"However, socialism has a secondary meaning that is harder to explain – government regulations, supervision of the private economy," Hayward said. "The problem now with Obama is, `What does he really think?'"

Ezra Klein, a blogger and columnist for The Washington Post, tackled the issue recently in a posting headlined "Barack Obama: Worst. Socialist. Ever."

Klein cited data indicating that the government sector of the economy shrank during the past three years.

"If President Obama is truly a socialist," Klein wrote, "then he's not a very good one."

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David Crary can be followed on Twitter at http://twitter.com/CraryAP

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