A much more effective attack, and much more worthy of the Republican attack machine.
Understand, the effectiveness of the Republican attack mchine is that it focuses heavily on tribalism. Unlike Democratic attack ads, which are just stupid venting without much real consideration for effectiveness, Republican attack ads are carefully designed to create negative feelings about Democratic candidates as a "them" rather than an "us."
The Ayers thing on its own is fairly stale and as a stand alone, does little beyond reenergize the core base. But when combined with this FEC complaint, it is clear that it is meant to reenforce to independents and undecideds that Obama is not "really one of us." This plays at many levels, turning his popularity abroad against him (after all, if those foreign people love him so much how can he be a "real American"), the usual subtext about name and race, and the other things designed to reenforce otherness.
Remember, it is not necessary to convince, it is only necessary to sew doubt. Create doubt and separation about the Democratic candidate and it colors the substantive inputs and (almost as a necessary counter reaction) draws the undecided closer to the Republican candidate.
The Ayers business is the distraction, it is the cumulative effect of the FEC charge (which will not be acted on until well after the election, preventing it from being effectively disproved or settled and resolved) and the other aspects that emphasize the "otherness." The FEC charge, by creating a far more effective line of doubt over Obama's "real American" status, makes the other charges -- no matter how old, tired, or refuted -- seem more credible. It is plausible, and plausibly suggests non-American (and therefore anti-American) influences. "How can someone beholden to foreign contributors be a good President" is the line of reasoning, and since it is an official complaint (but one that will not be resolved), it carries an imprimatur of authenticity.
The question is whether this election is so radically different in focusing voters on substance that these lines of attack are blunted. It is also coming late in the game, when the Republicans can be portrayed as desperately trying to avoid the real issues. Combined with a focus on Troopergate (the luster is sufficiently off the Palin rose to make this in play again for the undecideds), it can be made to appear that the Republicans are trumping up false charges to move the focus away from the "real" charges. That the Troopergate charges are no more or less proven than the FEC complaint is difficult to argue, since the Republicans will have engaged in the exact same conduct.
Normally, the tit-for-tat alienation of voters plays into R hands. But many things are reversed this election, including the usual proportions of registered and energized voters. Generic voter suppression of independents (rather than targeted suppresssion, which is likely to be much less effective this year) is more likely to benefit Democrats this year.
Meanwhile, reality will continue to bring surprises that neither party can anticipate. Should be a fune few weeks.