Pressing his efforts to raise doubts about Barack Obama’s character, John McCain has again questioned Obama’s association with a former war protester linked to Vietnam-era bombings. Unleashing a fresh round of attacks on his Democrat rival’s contacts, Republican McCain said that the questions being raised are part of a broader issue of honesty.

McCain’s attacks on Obama’s relationship with the 1970s radical, William Ayers, came at his address to a 4,000-people gathering at a sports complex near Milwaukee. He said that Ayers had helped found the Weather Underground, a Vietnam protest group that bombed government buildings four decades back.  

This was McCain’s strongest personal criticism of Obama, alleging that Obama had not been truthful in describing his relationship with Ayers - Obama having noted that he was a child when he first met Ayers and his wife, ex-radical Bernadine Dohrn, a quarter-century after the bombings. The Arizona senator said: “We don’t care about an old, washed-up terrorist and his wife. That’s not the point here.” He also added that Obama himself has “a clear radical, far-left pro-abortion record.”

McCain and the Republican National Committee also launched new Web and TV ads about Obama and Ayers. The ads say: “Barack Obama and domestic terrorist Bill Ayers - Friends. They’ve worked together for years.”

Talking to ABC News, McCain said: “We need to know the full extent of the relationship. It’s a factor about Senator Obama’s candor and truthfulness with the American people.”

Obama spokesman Bill Burton told the Fox News Channel that Obama was unaware about Ayers’ past when he went to his house. He further added that and that the Democratic presidential candidate found Ayers’ radical activities “detestable and deplorable.”

McCain is trailing in national polls, and Burton said: “American voters and American taxpayers understand what’s really going on in this race, which is that John McCain, as his campaign has said over and over again, does not want to talk about the economy, because if they do, they lose.”

Meanwhile, Obama himself has denounced Ayers and his violent actions and views. He dismisses McCain’s criticism as an effort to “score cheap political points.”