'60s Radical Ayers Among Subjects of McCain 'Robo-Calls'

"I don't care about an old washed-up terrorist," McCain said during the debate, but he added that Obama has not been open about the "full extent of that relationship."

Obama challenged the suggestion that he had spent time "palling around with terrorists," as Palin charged at a campaign rally, and said Ayers "engaged in despicable acts with a radical domestic group."

Ayers, now a Chicago professor, held an event at his house for Obama early in the Illinois Democrat's career, and the two have served together on a school reform board, but Obama said they are not close.

That McCain has made the issue the subject of robo-calls, Geer said, "reflects how much the McCain campaign really wants to get this message out. They're just trying it from every angle."

Meanwhile yesterday, the campaigns battled over other campaign tactics.

In a conference call, McCain campaign manager Rick Davis said the reports about investigations of the community organizing group ACORN (the Association of Community Organizations for Reform Now) suggested "rampant voter fraud as it relates to voter registration."

During the debate, Davis said, Obama had a chance to clarify his associations with ACORN but chose instead to "create a fog around the issue by not taking the opportunity to spell out his historical relations" with the group.

Davis then went on to say that on Election Day "and the day after," people have to be able to believe that they had "a fair and honest election" and that the person they chose "seems not to have a cloud hanging over this election." He later said that "when John McCain gets elected president," the party wanted to be sure the election process was the best it could be.

For the past two weeks, the RNC has steadily ratcheted up its response to the ACORN voter registration drives, sending out seven media advisories before Wednesday's debate questioning tactics used in ACORN registration drives.

In a conference call this week, Obama campaign manager David Plouffe said Republicans' ACORN attacks are part of "pulling out their old playbook."

"I think what they're doing right now is a form of intimidation, which is to raise a lot of questions out there, create a lot of confusion, and I think it's in the interest of trying to intimidate voters," he said.

The Democrats called for their own investigation.

Robert F. Bauer, the Obama campaign's general counsel, asked Attorney General Michael B. Mukasey to expand a special prosecutor's investigation to include a leak about the FBI investigating ACORN on suspicion of voter fraud.