Republican presidential candidate John McCain is striking hard on Democrat Barack Obama's connection to former 1960's radical William Ayers.
Ayers helped found a terrorist group known as the Weather Underground, whose members were accused of plotting and carrying out bombings on government buildings more than 30 years ago.
Obama insists he was very young at the time and did not know about Ayer's past.
"Ultimately I ended up learning about the fact that he had engaged in this reprehensible act 40 years ago," Obama told a Philadelphia talk radio show audience on Thursday. "But I was eight-years-old at the time and I assumed that he had been rehabilitated."
The Obama-Ayers connection has come up before. During one Democratic primary debate in April, Obama said Ayers was "a guy who lives in my neighborhood, who's a professor of English in Chicago, who I know and who I have not received some official endorsement from. He's not somebody who I exchange ideas from on a regular basis."
McCain: It's About Obama's Honesty
But McCain says that the Obama-Ayers relationship is part of a broader issue of honesty. He spoke about the issue in an interview with ABC News.
"He launched his political career in his living room, in Mr. Ayers' living room," McCain told anchor Charles Gibson. "And Americans should care, about his relationship with him and whether he's being truthful and candid about it. It's a factor about Sen. Obama's candor and truthfulness with the American people."
A new McCain television commercial hammers home the point. The portion of the TV ad says "When convenient, he worked with terrorist Bill Ayers. When discovered, he lied."
The commercial also says Obama's link to Ayers shows his blind ambition and bad judgment.
Obama's Campaign: Trying to Avoid Controversy?
Meanwhile, the Illinois senator has so far skirted the issue Polls show him leading in several battleground states.
Addressing an outdoor audience in Chillicothe, Ohio on Friday, Obama said McCain was trying to divide the country.
"It's not hard to rile up a crowd by stoking anger and division," Obama told the crowd. He said Americans want "someone who can lead this country" with a steady hand in a time of economic crisis, not divide it.
In his speech, he did not mention the McCain attack ads for associating with Ayers. Instead, he let two high-profile supporters take jabs at McCain.
Ohio Gov. Ted Strickland told the crowd, "The McCain-Palin campaign and some of their followers unfortunately want you to be afraid of Barack Obama."
Ohio's gun owners, Strickland said, "have nothing to fear from Barack Obama." Nor do people who revere "family and faith," he said, calling Obama "a strong Christian, family man."
Sen. Sherrod Brown, D-Ohio, also criticized the Arizona senator by name, saying the GOP nominee learned his economic lessons from The Wall Street Journal's conservative editorial pages.
Sources: CBN News, The Associated Press