If you've watched television or paid attention to your mail in an election year, chances are you've seen or heard one of those political ad disclaimers. They come in many different varieties, but the most common is a straightforward declaration by the candidate who sponsored the ad: "I approve this message."

So why do candidates for Congress and president say those words, which mostly state the obvious? They're required to. Federal campaign finance rules require political candidates and special-interest groups to disclose who paid for the political advertisement. So when Barack Obama appeared in a campaign commercial during the 2012 presidential election, he was required to state: "I'm Barack Obama and I approve this message."

The political ad disclaimers have done little to bring transparency to many of the most negative political ads, though — those launched by super PACs and other shadowy special interest who specialize using dark money to influence voters. The rules also don't apply to political ads on social media.

Studies have shown the disclaimers have done little to make campaigns more positive because candidates are increasingly brazen, coarse and unafraid to throw mud on their opponents, even if the claims are dubious and unsubstantiated.

Origins of Stand By Your Ad Law

The law that requires candidates to state I approve this message is commonly referred to as "Stand By Your Ad." It is an important component of the Bipartisan Campaign Finance Reform Act of 2002, a sweeping statutory effort to regulate the financing of federal political campaigns. The first ads to contain the Stand By Your Ad disclaimers appeared in the 2004 congressional and presidential elections. The phrase "I approve this message" has been in use ever since.

The Stand By Your Ad rule was designed to cut down on the number of negative and misleading advertisements by forcing political candidates to own up to the claims they make on television, radio and in print. Lawmakers believed many political candidates would not want to be associated with mudslinging for fear of alienating voters. "I will bet this: there will be moments in the studios when the candidates say to the producers of the ads, 'I'll be damned if I'm going to put my face on that,'" said Democratic Sen. Dick Durbin of Illinois, who was instrumental in getting the provision signed into law.

Examples of Political Ad Disclaimers

The Bipartisan Campaign Finance Reform Act requires political candidates to use the following statements to comply with the Stand By Your Ad provision:

"I am [Candidate Name], a candidate for [office sought], and I approved this advertisement."

Or:

"My name is [Candidate Name]. I am running for [office sought], and I approved this message."

The Federal Election Commission also requires television ads to include "a view or image of the candidate and a written statement at the end of the communication."

Political campaigns have gotten creative about circumventing the regulations, though. Some candidates now go well beyond the standard "I approve this message" disclaimer to attack their opponents.

For example, in the 2006 congressional race between Republican U.S. Rep. Marilyn Musgrave and Democratic challenger Angie Paccione, Paccione used the required disclaimer to go negative on the incumbent:

"I'm Angie Paccione, and I approve this message because if Marilyn keeps lying about my record, I'll keep telling the truth about hers."

In a New Jersey Senate race that year, Republican Tom Kean inferred that his Republican opponent was corrupt by using this line to fulfill the disclosure requirement:

"I'm Tom Kean Jr. Together, we can break the back of corruption. That's why I approved this message."

Stand By Your Ad Doesn't Really Work

In a 2005 study, the Center for the Study of the Presidency and Congress found that the Stand By Your Ad rule had "no effect on respondents' levels of trust in candidates or the ads themselves."

Bradley A. Smith, a professor at Capital University Law School in Columbus, Ohio, and chairman of the Center for Competitive Politics, wrote in National Affairs that Stand By Your Ad was having negative effects on the political process:

"The provision has failed miserably to curb negative campaigning. In 2008, for example, researchers at the University of Wisconsin found that more than 60% of Barack Obama's ads, and more than 70% of ads for John McCain — that great crusader for restoring integrity to our politics — were negative. Meanwhile, the required statement takes up almost 10% of every costly 30-second ad — reducing a candidate's ability to say anything of substance to voters."

Research has also found that Stand By Your Ad has boosted the credibility of attack ads, having the opposite effect intended under the law. Researchers at the University of California-Berkeley’s Haas School of Business found that “the tagline, far from disincentivizing negativity in advertising, has actually made it surprisingly effective,” according to study co-author Clayton Critcher.