On Friday, the McCain campaign released this attack ad against Barack Obama, in which the Democratic nominee's ties to former Weatherman Bill Ayers is revisited after a nice two-month hiatus from this non-issue.

But you won't think it's a non-issue if you take the ad at face value.

You'll probably think it's serious business, a grave political matter, and a clear indication that Barack Obama is a terrorist himself. Why else would he cavort with someone as unsavory, unAmerican and heartless as Bill Ayers?

Here are a few reasons I can think of without even glancing at the Obama campaign's response to the ad or anything else:

One: Proximity. Although I didn't know them, I was also a neighbor of Bill Ayers, Barack Obama, Reverend Jeremiah Wright and even Louis Farrakhan for that matter -- first as a graduate student, and then as a member of the community. Am I a dangerous person? (I realize you can't answer that, but no, I'm not.)

This was in Hyde Park, on the South Side of Chicago, home to the University of Chicago, where Ayers and Obama both have homes. It's the kind of neighborhood where people bump into each other at the local produce stand, or a bookstore, and wind up chatting for an hour about Lacanian psychoanalysis or political theory.

It's the kind of place where world-famous theologians walk their dogs with people who work in the department where they first split the atom. It's the kind of neighborhood with only one dive bar and one upscale bar.

I once had a few beers at the dive bar with Bill Ayers' adopted son, whose own mother was sent to prison for her involvement with the Weathermen. She asked Ayers and his wife, Bernadine Dohrn (who teaches law at Northwestern, by the way), to raise him. Does this make me an accomplice, too?

In short, it's a university town. And in university towns, academics know other academics, especially if they might work in fields that are of interest to one another.

Two: Conversation. Bill Ayers is a professor of education at the University of Illinois at Chicago, and education has been among Obama's central issues since he announced his candidacy. Is it so far-fetched to think that when Obama and Ayers did stop for a chat on a leafy sidewalk in Hyde Park -- regardless of how frequently it happened -- they talked of education, not how to blow up another government building?

Three: Professional Respect. Let's think about Ayers for a minute. His talents and dedication to his profession were enough to get him a job teaching future educators at a school renowned for its education program. He is taken seriously in this role, and his integrity hasn't been an issue for 30 years. Sounds like someone I wouldn't mind having coffee with now and then -- why not Barack Obama?

According to the McCain campaign, Ayers is a dangerous radical, and Obama's association with him, however slight, means Obama has a hidden agenda.

I have a question for the McCain campaign: Shouldn't you also be worried about all the colleagues Ayers has at UIC, his students, his children, and anyone else that's come into contact with him? If you're really worried about Obama's integrity, isn't that just the tip of the iceberg? Aren't you afraid that throughout this country, there may be secret cells of domestic terrorists -- teachers, college administrators, dentists, lawyers and secretaries -- plotting to destroy this country from the inside out?

If you are, then maybe you ought to be launching attacks against them, too, for having known Bill Ayers at some point in their lives. And while you're at it, go after all the people his wife knows, too.

But if you aren't, give the allegations against Obama a rest. Not only are they preposterous, but they suggest that you don't care about all the other people Ayers knows, which frankly undermines your entire attack. Because if associating with him really does make someone a threat, we're already screwed.