In a campaign year when voters have declared the economy their top concern, Obama and Mitt Romney are on notice that there's no statute of limitations on the issues or conduct that might be used against them. And there's sure to be somebody with money or other means to insert even low-threshold matters into the political dialogue.
"It's open season," says Eric Dezenhall, an expert on crisis management. "This is going to be very rough."
Thursday's disclosure that a Republican-leaning super PAC was considering a $10 million ad campaign highlighting Obama's past links to inflammatory preacher Jeremiah Wright was just the latest evidence that if there ever were limits on what was fair game in a campaign, they're largely history.
That's thanks to a flood of new money into politics, the ease of spreading political attacks via the Internet and changing attitudes about what's an appropriate topic for discussion. Long gone are the days when candidates' extramarital escapades were off-limits, photographers avoided taking pictures of Franklin D. Roosevelt in a wheelchair and a few newspapers and TV stations acted as gatekeepers.
The New York Times quoted backers of this year's Wright ad proposal as aiming to "do exactly what John McCain would not let us do" in the 2008 campaign.
Romney repudiated the Wright plan, as did the super PAC financier weighing it. Nonetheless, Obama's campaign accused Romney of refusing to "stand up to the most extreme voices in the Republican Party" and the president's supporters were happy to associate Romney with what campaign strategist David Axelrod called the "purveyors of slime."
McCain, the 2008 GOP nominee, spoke out forcefully during the campaign four years ago against efforts to use Wright's provocative speeches against Obama, and the issue largely subsided. But since then, a series of court cases has cleared the way for an onslaught of campaign ads from outside groups seeking to influence elections.
Such so-called super PACs can be a megaphone for matters that would have gotten less attention in the past, and still allow candidates to deny they're involved.
But outside messengers who do the dirty work in campaigns are nothing new in presidential politics. Democrat Michael Dukakis in 1988 was the target of an infamous outside ad about a furloughed rapist named Willie Horton. Democrat John Kerry in 2004 saw his record as a Vietnam War hero mischaracterized and used against him by the outside group Swift Boat Veterans for Truth.
Political historian Evan Cornog, author of "The Power and the Story," said the staying power of a particular issue or charge usually depends on whether it jibes with the public's understanding of a candidate.
"We are addicted to narratives, and if something fits with the story, it's going to get some traction," says Cornog. "A good political operative will have a fairly good sense of what will work and what will not work."
Both sides are experiencing this in real time:
--Questions about Romney's bad behavior toward classmates during his high school years, revealed in a recent Washington Post article, are being used to reinforce the profile that Romney's critics have tried to create of the GOP candidate as a corporate bully. The Democratic National Committee circulated the Post article and highlighted just one sentence about Romney's behavior: "It was vicious."
--Questions about Obama's ties to his former preacher's incendiary rhetoric about America and about whether the president was truly born in Hawaii and is a Christian fit with broader efforts to paint Obama as radically different from most Americans. Romney earlier this year told an interviewer, "I'm not sure which is worse, him listening to Reverend Wright or him saying that we must be a less Christian nation." That was a reference to remarks in which Obama actually did not promote a less Christian nation but observed growing religious diversity in the U.S.
When something nicely fits with the profile that one side or the other is trying to build, it may endure long after a question has been duly asked and answered.
Questions about the validity of Obama's Hawaii birth certificate, for example, have been widely discredited, they but keep popping up. Donald Trump and Texas Gov. Rick Perry both toyed with it during the presidential primaries. A poll last May, after Obama had released his detailed Hawaii birth certificate, found that a third of Americans still thought he might have been born elsewhere or said they didn't know.
Cornog points to plenty of positive aspects to the free-wheeling exchange of ideas and information allowed by a broad variety of news sources and the Internet but also has a warning: "If you enter an age in which you have elective belief systems independent of fact, you have a problem for your political world."