Barack Obama laughs off charges of socialism. Joe Biden scoffs at references to Marxism. Both men shrug off accusations of liberalism.

But Obama himself acknowledges that he was drawn to socialists and even Marxists as a college student. He continued to associate with Marxists later in life, even choosing to launch his political career in the living room of a self-described Marxist, William Ayers, in 1995, when Obama was 34.

Obama's affinity for Marxists began when he attended Occidental College in Los Angeles.

"To avoid being mistaken for a sellout, I chose my friends carefully," the Democratic presidential candidate wrote in his memoir, "Dreams From My Father." "The more politically active black students. The foreign students. The Chicanos. The Marxist professors and structural feminists."

Obama's interest in leftist politics continued after he transferred to Columbia University in New York. He lived on Manhattan's Upper East Side, venturing to the East Village for what he called "the socialist conferences I sometimes attended at Cooper Union."

After graduating from Columbia in 1983, Obama spent a year working for a consulting firm and then went to work for what he described as "a Ralph Nader offshoot" in Harlem.

"In search of some inspiration, I went to hear Kwame Toure, formerly Stokely Carmichael of Black Panther fame, speak at Columbia," Obama wrote in "Dreams," which he published in 1995. "At the entrance to the auditorium, two women, one black, one Asian, were selling Marxist literature."

Obama supporters point out that plenty of Americans flirt with radical ideologies in college, only to join the political mainstream later in life. But Obama, who made a point of noting how "carefully" he chose his friends in college, also chose to launch his political career in the Chicago living room of Ayers, a domestic terrorist who in 2002 proclaimed: "I am a Marxist."

Also present at that meeting was Ayers' wife, fellow terrorist Bernardine Dohrn, who once gave a speech extolling socialism, communism and "Marxism-Leninism."

Obama has been widely criticized for choosing the Rev. Jeremiah Wright, an anti-American firebrand, as his pastor. Wright is a purveyor of black liberation theology, which analysts say is based in part on Marxist ideas.

Few political observers go so far as to accuse Obama, the Democratic presidential nominee, of being a Marxist. But Republican John McCain has been accusing Obama of espousing socialism ever since the Democrat told an Ohio plumber named Joe earlier this month that he wanted to "spread the wealth around."

Obama's running mate, Biden, recently contradicted his boss, saying: "He is not spreading the wealth around." The remark came as Biden was answering a question from a TV anchor who asked: "How is Senator Obama not being a Marxist if he intends to spread the wealth around?"

"Are you joking? Is this a joke? Or is that a real question?" an incredulous Biden shot back. "It's a ridiculous comparison."

But the debate intensified Monday with the surfacing of a 2001 radio interview in which Obama lamented the Supreme Court's inability to enact "redistribution of wealth" -- a key tenet of socialism. On Tuesday, McCain said Obama aspires to become "Redistributionist-in-Chief."

Obama has managed to cultivate the image of a political moderate in spite of his consistently liberal voting record. In 2006, he published a second memoir, "The Audacity of Hope," that leaves little doubt about his adherence to the left.

"The arguments of liberals are more often grounded in reason and fact," Obama wrote in "Audacity." "Much of what I absorbed from the sixties was filtered through my mother, who to the end of her life would proudly proclaim herself an unreconstructed liberal."

National Journal magazine ranked Obama as the most liberal member of the Senate. The publication is far from conservative, employing such journalists as Linda Douglass, who resigned in May to become Obama's traveling press secretary.