“Obama denies any video showing Michelle 'whitey' rant...” So reads the headline on the DrudgeReport. Check it out.

For weeks I’ve been hearing that Republicans had gotten their hands on a video in which Sen. Barack Obama's wife, Michelle Obama, goes on a tirade against “whitey.” According to various versions of the story, it was a video from Trinity Church, undated, that the supersleuths of the Republican negative research team had been able to uncover, much to the frustration of their less effective counterparts in the Clinton campaign.

But rather than let it out at a time when it could cost Obama the nomination, and have their man end up facing Hillary, they were holding on to it to use in the general election.

I heard it from all kinds of people — Republicans, Democrats, Hillary supporters and worried Obama-ites. It was, not surprisingly, all over the Internet.

Only one tiny problem: As far as I could tell, looking at all the places and sites reporting the rumor, there was not a shred of evidence to support it. No one who was talking about it had actually seen the tape.

No one who knew Michelle Obama believed it was true. No one who knew the capacity of the Clinton research team could understand how, if it were true, only the Republicans would know it.

No one who understands the impossibility of keeping things secret in politics could believe that the strategy of holding on to damning evidence actually could work in 2008.

Most people who understand the way Republicans think weren’t at all sure they actually would prefer to face Obama rather than Hillary in the fall. In other words, it had all the earmarks of one of those rumors that just ain’t so.

Which did not stop it from spreading. And spreading. To the point that, finally, a “legitimate” reporter asked Obama about it.

His answer essentially said what mine did: that it was a ridiculous question because there wasn’t one shred of evidence to support the rumor. Which, of course, turned the rumor, or at least the denial of the rumor, into legitimate news, which then was all over even the more “legitimate” media, which no doubt will leave some people who don’t read carefully, or believe that where there’s smoke there must be fire, concluding that Michelle Obama must have gone on a whitey rant. Even if she didn’t.

I’d like to be able to blame the Internet and bloggers and all the newcomers to the political scene for turning rumors into news, but it’s not so.

On the day he was sworn in as speaker of the House, Tom Foley was forced to hold a news conference denying rumors that originated in Newt Gingrich’s office claiming that he was gay. “I didn’t know Tom Foley was gay," my own mother said to me later that day.

What made the rumor news was that a columnist had written a story decrying the fact that Gingrich’s office was spreading the rumor. Then the rest of the press reported on the column decrying the rumor, which gave the rumor the legs to have to be denied. On the very day he took office!

In 1988, the Dukakis campaign was dogged by two rumors later tied to the Republican National Committee: that the candidate’s wife, Kitty Dukakis, had burned a flag at an anti-war demonstration (which became legitimate news when a Republican senator repeated it) and that the candidate, himself, had been treated for depression after losing his bid for re-election as governor of Massachusetts 10 years earlier.

The latter rumor, which like Michelle Obama’s “whitey” rant had not one shred of evidence to support it, spread so far and wide that then-President Reagan considered it appropriate for an “inside” joke at a press conference, which, of course, made it news requiring a denial.

When Reagan was asked a question about Dukakis’ position on some issue, he responded by saying he didn’t want to make a comment about an “invalid,” which required everyone to explain why the president would refer to the Democratic nominee as an “invalid,” which required me to buy a new tie for Dukakis’ personal physician to wear on his round of television interviews in which he repeatedly explained that, no, Dukakis never had been treated for anything by a psychiatrist.

The local news that night could not have been worse: Dukakis not crazy, more at 11. Nationally, it wasn’t much better. We dropped nearly 10 points overnight. To this day, I’m sure there are people who vaguely can remember the business about Dukakis having psychiatric issues — not that he didn’t.

Barack Obama absolutely was right when he told the reporter last week that he shouldn’t have to deny a rumor that had not one shred of evidence to support it, that even asking him the question, and his having to answer it, turns garbage into news, and give rumors a credence they don’t deserve.

“We have seen this before, Obama rightly pointed out. “There [are] dirt and lies that are circulated in e-mails and they pump them out long enough until finally you, a mainstream reporter, asks me about it,” he said to the McClatchy reporter who asked him about it during a press conference aboard his campaign plane.

“That gives legs to the story. If somebody has evidence that myself or Michelle or anybody has said something inappropriate, let them do it.” That didn’t end it. Why would it? Asked whether he knew the rumor to be not true, Obama said he had answered the question.

“Frankly, my hope is people don’t play this game. It is a destructive aspect of our politics. Simply because something appears in an e-mail, that should lend it no more credence than if you heard it on the corner. Presumably the job of the press is to not to go around and spread scurrilous rumors like this until there is actually anything, an iota, of substance or evidence that would substantiate it.” Dream on.

While McCain also has been the target of rumors (remember the illegitimate child he didn’t have), it is Obama who is most vulnerable at this point, for the simple reason that the less well-known you are, the more vulnerable you are to being painted into a corner, even a rumor-filled one.

This campaign is just beginning, and “whitey” isn’t the first or last rumor that will dog the candidate.

There always will be some reporter who will ask the question, and the candidate will be damned if he does (a denial is news) and damned if he doesn’t (refusing to address it can only add fuel).

The only answer is for those of us who hear these things, which in this day and age is anyone with even a small appetite for political news, to remember that in this business, smoke is just that.

Susan Estrich is the Robert Kingsley Professor of Law and Political Science at the University of Southern California. She was Professor of Law at Harvard Law School and the first woman President of the Harvard Law Review. She is a columnist for Creators Syndicate and has written for USA Today and the Los Angeles Times.

Estrich's books include the just published "Soulless," "The Case for Hillary Clinton," "How to Get Into Law School," "Sex & Power," "Real Rape," "Getting Away with Murder: How Politics Is Destroying the Criminal Justice System" and "Making the Case for Yourself: A Diet Book for Smart Women."

She served as campaign manager for Michael Dukakis' presidential bid, becoming the first woman to head a U.S. presidential campaign. Estrich appears regularly on the FOX News Channel, in addition to writing the "Blue Streak" column for FOXNews.com.

Susan Estrich is currently the Robert Kingsley Professor of Law and Political Science at the University of Southern California and a member of the Board of Contributors of USA Today. She writes the "Portia" column for American Lawyer Media and is a contributing editor of The Los Angeles Times. She was appointed by the president to serve on the National Holocaust Council and by the mayor of the City of Los Angeles to serve on that city's Ethics Commission. A woman of firsts, she was the first woman president of the Harvard Law Review and the first woman to head a national presidential campaign (Dukakis). Estrich is committed to paving the way for women to assume positions of leadership. Books by Estrich include "Real Rape," "Getting Away with Murder: How Politics is Destroying the Criminal Justice System" and "Dealing with Dangerous Offenders." Her book "Making the Case for Yourself: A Diet Book for Smart Women," is a departure from her other works, encouraging women to take care of themselves by engaging the mind to fight for a healthy body. Her latest book, The Los Angeles Times bestseller, "Sex & Power," takes an impassioned look at the division of power between men and women in the American workforce, proving that the idea of gender equality is still just an idea.