Even by the shabby standards of this presidential campaign, it's outrageous for Sarah Palin to assert that Barack Obama is so deficient in patriotism that he would "pal around with terrorists who bomb their own country." Obama was wrong to associate with Bill Ayers, a founder of the Weather Underground, but the suggestion that the two are political soul mates is absurd and insulting. John McCain should think twice before polluting tonight's second presidential debate with this noxious falsehood.

On Saturday, Palin said of Obama that she'd read that "one of his earliest supporters is a man who, according to the New York Times, was a domestic terrorist, that, quote, 'launched a campaign of bombings that would target the Pentagon and the United States Capitol.' " Palin offered her own sinister spin: "This is not a man who sees America as you and I see America. We see America as a force for good in this world. ... Our opponents see America as imperfect enough to pal around with terrorists who would bomb their own country."

For some time, Obama's more feverish critics have been suggesting that he condones Ayers' involvement with terrorist bombings in the 1970s and that Ayers continues to exert influence over the Democratic nominee. McCain tried out the accusation in April. Never mind that, according to the article that supposedly caught Palin's eye, the two men aren't close and haven't spoken since 2005.

Obama displayed not just poor political judgment but a lack of moral imagination in associating with Ayers -- even in an uncontroversial school reform effort -- and allowing Ayers and his wife to host a coffee event in connection with his first run for public office. Charges that Ayers had conspired in bombings and crossed state lines to incite a riot were dropped because of misconduct by prosecutors, but he has refused to apologize for the violence committed by the Weathermen. In an interview with the New York Times published Sept. 11, 2001, of all dates, Ayers said: "I don't regret setting bombs. I feel we didn't do enough."

Although Ayers was reincarnated as an academic, when his path and Obama's crossed, the budding politician should have recognized that his Chicago neighbor was radioactive. But their association should not be distorted. There is no evidence that Obama shared Ayers' approval of violence or his views about whether America is "a force for good in this world." For Palin and McCain to insinuate otherwise is a 21st century form of McCarthyism.