In an 2004 Democtatic presidential campaign ad, nominee John Kerry said, "I am John Kerry, and I am reporting for duty!"

Senator John Kerry of Massachusetts was the Democratic Party's presidential candidate in 2004, running against incumbent Republican President George W. Bush. But in the months just before the November election, a swarm of attack ads critical of Kerry's Vietnam war military service, and his later opposition to that war, appeared on TV.

Outside Groups Add TV Presence to Political Contests

"John Kerry betrayed the men and women he served with in Vietnam."

Outside Groups Add TV Presence to Political Contests

"He [John Kerry] dishonored his country. He most certainly did."

Outside Groups Add TV Presence to Political Contests

"I served with John Kerry. John Kerry cannot be trusted"

These TV ads did not come from President Bush's re-election campaign. They were created by an independent political interest group called . And, political observers say, the ads played a part in John Kerry's loss to Mr. Bush.

Swift Boat Veterans for Truth and similar political interest groups are often called "527s" because they fall under that section of the U.S. tax code.

And, the use of 527s in campaigns cuts across partisan lines. In 2004, a group called launched attack TV ads against President Bush and his policies.

"Christmas is coming early to George Bush's big contributors. Drug companies got high prices in the Medicare [health coverage] bill. Defense companies got no-bid contracts in Iraq. Yes, big contributors, there is a Santa Claus."

To critics, 527 groups give candidates and their campaigns the ability to engage in mudslinging or vicious attacks without being held directly accountable.

Peter Fenn, a political communications consultant for Democrats says, "Most of these so-called independent groups are not independent at all. They may not be working on direct orders from the candidate or the party, but they know what the issues are. They are part and parcel of the campaign.

But other political analysts disagree. Brian Darling is one. He is with the conservative Washington, D.C. research group The Heritage Foundation and says, "They are completely uncontrolled by campaigns, and there is a concern that these independent groups may run ads that nobody can control, and it takes over the message of each candidate."

527 groups do not just operate during presidential campaigns. They also work at the state level. A conservative anti-tax group called stepped into a 2006 U.S. Congress race in the state of Ohio.

"Who will stop the waste and stand up for taxpayers? 'Tax and Spend' Bob Latta, or conservative Steve Buehrer?"

Some political observers say that because 527 groups were so effective, we can well expect similar independent attack ads on both sides in the 2008 race for the White House.