John McCain is asking a lot of questions about William Ayers. But that doesn't mean he's actually looking for answers.

After a week or so of letting running mate Sarah Palin obsess on the campaign trail over the meaning of Barack Obama's "association" with the unrepentant Weather Underground founder--last week she accused Obama of "palling around with terrorists," for example--McCain himself finally entered the fray yesterday, namedropping Ayers in a new Internet ad, at a rally in Wisconsin and in an interview with ABC's Charlie Gibson.

"We need to know the full extent of the relationship" to judge "whether Senator Obama is telling the truth to the American people or not," McCain said in Wisconsin.

"Where's the truth, Barack?" asked his Web ad.

“I don't care about two washed-up old terrorists that are unrepentant about trying to destroy America," he told Gibson. "But I do care, and Americans should care, about his relationship with him and whether he's being truthful and candid about."

You'll notice that McCain never really bothered to say what we don't know about Obama and Ayers--let alone why what we don't know matters, or what Obama isn't telling the truth about. The point, it seems, is to create a false air of mystery around the Obama-Ayers relationship--and encourage voters to fill in the blanks with their own biases, suspicions and fears. It's the same reason McCain keeps asking "Who is Barack Obama?"

Here's how the strategy works. First, say the word "terrorist." Then characterize the Obama-Ayers relationship as murky, assuming that listeners don't know--or don't care to find out--that Obama has already characterized Ayers' past as "detestable" and discussed how the two crossed paths in Chicago. Next, insinuate that Obama's alleged evasions--and the mere fact that he encountered Ayers at all--call his character into question. And--last but not least--hope voters conclude that Obama is some sort of radical left-wing terrorist-sympathizer unworthy of the Oval Office.

Ultimately, McCain is resorting to innuendo because when it comes to Ayers, he has more to gain from preying on ignorance than providing information. Despite McCain's insinuations about his rival's untruthfulness, the Obama-Ayers backstory isn't all that mysterious. Like other Ayers acquaintances, Obama initially knew the former radical only as a fixture of Chicago's mainstream school-reform community. They were introduced at a coffee Ayers hosted before Obama's first run for office. They served on a schools project and a charitable board together. And they occasionally bumped into each other the streets of Obama's Hyde Park neighborhood. Obama has been pretty clear about all of this--even if it's a subject he's tried to avoid--and objective observers say that "the two men do not appear to have been close." As William C. Ibershof, the chief prosecutor of the Weather Underground in the 1970s, put it in a letter this morning to the New York Times, "because Senator Obama recently served on a board of a charitable organization with Mr. Ayers cannot possibly link the senator to acts perpetrated by Mr. Ayers so many years ago."

Many conservative commentators agree. "Does anybody really seriously believe that Barack Obama is a secret left-wing radical?" former Bush speechwriter David Frum recently wrote. "And if not, then what is this fuss and fury supposed to show? It's like Ronald Reagan's opponents trying to beat him by pointing out that Birchers once supported him." Still, some right-wingers have seized on the most substantial link between the pair--their six years (1995-2001) serving together on the board of an educational foundation called the Chicago Annenberg Challenge--as evidence that Obama and Ayers once worked in tandem to advance a radical leftist agenda. "Those who argue that the Ayers connection is important because Ayers is an unrepentant terrorist are emphasizing the wrong part of the Ayers/Obama oeuvre," conservative blogger Neo-Neocon recently wrote. "It’s way too much of a stretch to say... that Obama was simpatico with Ayers’ terrorist past or with the extremity of his radical beliefs. Annenberg, however, was a whole nother ball game."

Unfortunately, the facts don't support that charge. 

According to the CAC critics--the most prominent being Stanley Kurtz of the National Review--the group's "agenda flowed from Mr. Ayers's educational philosophy, which called for infusing students and their parents with a radical political commitment, and which downplayed achievement tests in favor of activism." But while it's true that Ayers falls firmly on the left wing of the school-reform spectrum--he believes in "teaching for social justice and liberation" and recently praised Venezuelan President Hugo Chavez for working to overcome the "failures of capitalist education"--there's simply no evidence that the CAC (or, by extension, Obama) supported, shared or helped implement a particularly radical agenda in Chicago. "In fact," writes Education Week, "the project undertaken in Chicago as part of a high-profile national initiative reflected mainstream thinking among education reformers. The Annenberg Foundation’s $49.2 million grant in the city focused on three priorities: encouraging collaboration among teachers and better professional development; reducing the isolation between schools and between schools and their communities; and reducing school size to improve learning." Here's more from a 2003 report by the Chicago Consortium on School Research assessing the CAC's (rather limited) impact:

The Chicago Challenge did not articulate specific goals for individual school development, nor did it specify any specific activities or processes to follow. Rather, it believed that educators, parents and community members could and should identify their own ways to solve local problems and improve their schools. The Challenge initially encouraged schools to focus their efforts on three basic problems of school organization that were seen as obstacles to improvement: a) the lack of time for effective teaching, student learning and teacher professional development; b) the large size of school enrollments and instructional groups hindering the development of personalized, supportive adult-student relationships; and c) schools' isolation from parents and communities, which reduced their responsiveness to local needs and their accountability to their most immediate constituents.

Sound pedestrian? That's because it is. As conservative blogger Ross Douthat of the Atlantic has written, this is "as far as the Ayers issue can take you on substance, and it isn't very far at all." So it's no wonder that McCain and Co. have decided they'd rather shout "terrorist" in a crowded theater than start a convoluted (and ultimately fruitless) argument about left-wing activism and curricular battles in the Chicago school system.

Unfortunately for McCain, even the innuendo hasn't made much of an impact. As Nate Silver notes, "Obama's favorables decreased by an average of 1.7 points" between Oct. 3 and Oct. 8, "while his unfavorables increased by 1.3 points... well within the margins of error of the respective polls... By comparison, when the Jeremiah Wright story first broke on March 13, Barack Obama's favorables decreased by about 5 points within the span of a week, and his unfavorables increased by the same margin." After Tuesday's debate, the Illinois senator's approval ratings quickly ticked upward again.

It's true that McCain hasn't thrown the full force of his campaign behind the Ayers attack, choosing not to invest in TV advertising, deliver an all-Ayers stump speech or mention the guy in a debate. But he's right to be reluctant. The fact is, obsessing over Ayers may hurt McCain more than Obama at this point. As conservative columnist George Will writes in this morning's Washington Post, "the McCain-Palin charges have come just as ... many millions of American households are gingerly opening envelopes containing reports of the third-quarter losses in their 401(k) and other retirement accounts--telling each household its portion of the nearly $2 trillion that Americans' accounts have recently shed. In this context, the McCain-Palin campaign's attempt to get Americans to focus on Obama's Chicago associations seems surreal." Might an undecided voter see an Ayers ad and say to himself, "Man, that terrorist-sympathizing Obama can't be trusted in an economic crisis"? Possibly. But I suspect--like Douthat--that "McCain looks, to our hypothetical undecided, utterly disconnected from what's happening in the world, and the details of the Ayers connection, however troubling they might be in another context, blur away into a broader impression of a flailing, desperate, out-of-touch candidate." 

Perhaps it's time for the next question.

UPDATE, 9:17 p.m.: More from NEWSWEEK partner Factcheck.org:

In a TV ad, McCain says Obama "lied" about his association with William Ayers, a former bomb-setting, anti-war radical from the 1960s and '70s. We find McCain's claim to be groundless. New details have recently come to light, but nothing Obama said previously has been shown to be false... McCain says in an Internet ad that the two "ran a radical 'education' foundation" in Chicago. But the supposedly "radical" group was supported by a Republican governor and included on its board prominent local civic leaders, including one former Nixon administration official who has given $1,500 to McCain's campaign this year. Education Week says the group's work "reflected mainstream thinking" among school reformers. The group was the Chicago Annenberg Challenge, started by a $49 million grant from the Annenberg Foundation, which was established by the publisher Walter Annenberg, a prominent Republican whose widow, Leonore, is a contributor to the McCain campaign. (FactCheck.org, which is nonpartisan, also receives funding from the Annenberg Foundation. But we are in no way connected to the Chicago Annenberg Challenge, which finished its work long before we came into being in late 2003.)...

UPDATE, 10:34 p.m.: Just stumbled on this post by libertarian blogger Megan McArdle. She makes an excellent point:

I think that the Ayers connection is too tenuous to be interesting.  But there is a nugget of a real critique at its heart, which is that the academic culture Obama belongs to thinks it's just fine to be a former active terrorist who has refused to renounce support for the violence committed by his group; that culture has rewarded Bill Ayers with prestigious employment and other positions in a way that it wouldn't dream of rewarding a similarly "idealistic" abortion clinic bomber... If you're conservative, that seems like a real problem.

Was Ayers' behavior reprehensible? Absolutely. Should he, unrepentant, have been accepted in polite society? Absolutely not. But I don't think that swing voters will punish--or should punish--Obama for the excesses of liberal academic culture.