But the McCain campaign kept suggesting there was more to it. Whenever McCain officials were asked what more they knew, they would say only that they were certain the relationship was closer than Obama described it.
McCain's senior advisers, Steve Schmidt and Charles Black, kept saying that at some point, McCain would attack Obama over Ayers. Obama's controversial former minister the Rev. Jeremiah Wright was off-limits, they said, but not Ayers because Ayers was a terrorist.
On occasion, McCain campaign officials would bring up Ayers. In May, with McCain under fire from Obama and others for having former and current lobbyists in his campaign, his campaign fired back by citing Ayers.
"Just a few years ago when Barack Obama was beginning his career in politics, he was launched it a the home of William Ayers, an unrepentant terrorist," said Tucker Bounds, a McCain campaign spokesman. "If Barack Obama is going to make associations the issue, we look forward to a debate about Senator Obama's associations."
But the expected major attack never happened.
Then, this past summer, a conservative group called The American Issues Project, some of whose members had ties to the Swift Boat Veterans for Truth campaign that attacked Sen. John Kerry in 2004, spent $2.8 million on television ads in Ohio that sought to link Obama to Ayers.
Independently, in late August, Schmidt told ABC News that the McCain campaign planned to start hitting Obama with both Ayers and Tony Rezko, a Chicago developer and Obama friend who was convicted on federal corruption charges in June.
About Ayers, Schmidt said: "(Obama) understates his relationship with him. He does have a relationship which is deeper than what's previously said about it. It's a fair issue to discuss."
Again, the promised attack didn't come. What may have held it off is that the McCain camp and the Republican National Committee, which has also been looking for damage evidence of a Obama-Ayers relationship, has never been able to find much more to than what is known: Obama was at Ayers's house once 13 years ago. They served together on two boards. Their children went to the same school.