Republican John McCain was on the attack during much of the final presidential debate, assailing Democrat Barack Obama for ties to William Ayers, a Vietnam-era radical, and ACORN, a liberal-leaning group whose voter registration efforts have come under scrutiny.
But Obama's associations with both appear more tenuous than suggested by McCain and his running mate, Alaska Gov. Sarah Palin.
McCain said the public should know the full extent of Obama's relationship with an "old, washed-up terrorist" and the Assn. of Community Organizations for Reform Now, or ACORN, which the Republican senator accused of being "on the verge of maybe perpetrating one of the greatest frauds in voter history in this country."
Obama responded that Ayers, a Chicago professor who in 1969 co-founded the radical Weathermen group, engaged in "despicable acts" when Obama was 8 years old.
"Let's get the record straight," he said. "Mr. Ayers is not involved in my campaign. He has never been involved in this campaign, and he will not advise me in the White House."
Ayers has not publicly discussed the relationship, which Sen. Hillary Rodham Clinton (D-N.Y.) raised during the Democratic primary. William C. Ibershof, a former federal prosecutor who in the 1970s pursued a case against Ayers alleging conspiracy to bomb political targets, has called the persistent effort to link Obama to Ayers "manifestly unfair." A judge tossed out the charges against Ayers, citing illegal government activities.
Obama and Ayers live in the same Chicago neighborhood, and the professor hosted a party and contributed money to Obama's first political campaign in 1995. The two also served together on philanthropic boards. Ayers, 63, counts Chicago Mayor Richard M. Daley among his defenders.
The nonpartisan FactCheck.org, run by the Annenberg Public Policy Center of the University of Pennsylvania, recently said it found McCain's earlier claim that Obama "lied" about his association with Ayers to be "groundless."
FactCheck.org said the foundation on which Obama and Ayers served was supported by a Republican governor and included on its board prominent local civic leaders, including one former Nixon administration official who has given $1,500 to McCain's campaign this year.
Obama said his only involvement with ACORN was representing the group "alongside the U.S. Justice Department" in a lawsuit against the state of Illinois in the mid-1990s to force the state to implement a federal law allowing people to register to vote when they obtain a driver's license.
The Obama campaign has acknowledged that it paid more than $800,000 to a group affiliated with ACORN to augment get-out-the-vote operations during the Democratic primaries. But that group did not register voters, the Obama campaign said.
McCain also criticized Obama for his position on an abortion-related bill while a state legislator in Illinois.
"Sen. Obama, as a member of the Illinois state Senate, voted in the judiciary committee against a law that would provide immediate medical attention to a child born of a failed abortion. He voted against that," McCain said.
Obama said the bill would have undermined legal protections for abortion provided by Roe vs. Wade. He defended his vote by saying that "there was already a law on the books in Illinois that required providing life-saving treatment, which is why not only myself but pro-choice Republicans and Democrats voted against it."
Factcheck.org supports Obama's assertion that there was already a law protecting such babies and has criticized an ad by an antiabortion group featuring a woman who says she was born in a failed abortion. The woman says she would not be alive "if Barack Obama had his way."
Illinois law since 1975 requires that if a child is born alive during an abortion, the physician "shall exercise the same degree of professional skill, care and diligence to preserve the life and health of the child as would be required of a physician providing immediate medical care to a child born alive in the course of a pregnancy termination which was not an abortion."
Failure to do so is a felony in Illinois.
Times staff writer Dan Morain contributed to this report.