Alter: 2012 campaign is out of the gutter

Strangely enough, the 2012 presidential campaign, expected to be the dirtiest in modern memory, may end up being relatively clean.

That's because both sides agree that the economy is the central issue and that sideshows aren't persuasive for voters. Karl Rove and Larry McCarthy, the creator of the infamous Willie Horton ad, think harsh personal attacks against President Barack Obama will backfire, and they're offering more subtle messages of economic disappointment instead.

Even economic assaults can boomerang nowadays. Newark Mayor Cory Booker, an otherwise strong Obama supporter, dealt the president's campaign a blow last weekend on NBC's "Meet the Press" when he said he was "nauseated" by an Obama ad lambasting Mitt Romney's tenure at Bain Capital.

The controversy surrounding the Bain ad and a proposed ad about the Rev. Jeremiah Wright from a super PAC backed by Joe Ricketts, the billionaire founder of TD Ameritrade Holding Corp., suggests that when "paid media" in the presidential race ventures out-of-bounds, "free media" will exact a penalty. We can still expect a misleading and overwhelmingly negative campaign, but the distortions and outright lies will be mostly about the candidates' records and positions, not their race, religion and standing as patriotic Americans.

I don't mean to be pollyannaish, but that represents a step up from the gutter.

The days when Lyndon Johnson could use the infamous "daisy ad" to suggest Barry Goldwater wanted to blow up the world, or Vice President George H.W. Bush (and Al Gore before him) could exploit the racist Willie Horton story against Michael Dukakis, are over. In 2004, when Swift Boat Veterans for Truth could easily smear John Kerry's character by distorting his Navy service during the Vietnam War, you couldn't yet use YouTube and blogs to rebut an ad and even organize a boycott of the sponsors within hours. If the Swift Boat attacks aired today, President George W. Bush would probably be forced to denounce them.

This sounds counterintuitive. After the Supreme Court's Citizens United decision, the system is awash in super PACs that allow secret donations. Instead of clearly identifying the origin of the ad ("I'm Mitt Romney, and I approve this message"), the tag lines on the super PAC ads are from gauzy-sounding outfits ("Restore Our Future") that few people recognize. As we learned during the Republican presidential primaries, this has changed the tone of the campaign. About 70 percent of the ads in the presidential campaign from Jan. 1, 2011, to April 22, 2012, contained at least some negative content.

But neither candidate can afford to let his backers wander too far off the reservation. When Ricketts considered running a super PAC ad featuring Obama's relationship with his former pastor Wright, known for his controversial views, the proposed commercial leaked to the New York Times. The fallout may cost the Ricketts family trust, which owns the Chicago Cubs, the $150 million it was seeking from the City of Chicago to help fund the renovation of Wrigley Field. A furious Mayor Rahm Emanuel wouldn't even return phone calls from the Ricketts family.

The story sends a powerful message to other billionaires trying to play in the presidential election sandbox: Expect sand in your eyes.

The best way to avoid it -- and stay on good terms with the Romney campaign (which sees anything racial or personal about the president as counterproductive) -- is to go with approved (though technically not "coordinated") super PACs like those run by Rove and a group of Romney's former top aides. Rove's American Crossroads and Crossroads GPS, which so far this election cycle have raised more than $100 million, will probably have at least a couple hundred million to use trashing Obama -- often unfairly. But most of it will be spent on depicting the president as incompetent on the economy, not on personal attacks.

The near-universal condemnation of the proposed Wright ad also increases the likelihood that any comments about Romney's Mormon faith will be seen as off-limits.

When you're talking about the most powerful job in the world, all biographical facts -- relationships with old pastors, management of companies, religious practices, even old girlfriends -- are at least potentially relevant. But this year, with the country facing a stark choice in hard times, they will be derided as distractions from an unusually substantive campaign.