Democratic rivals Howard Dean (search) and Dick Gephardt (search) are pulling the negative ads they've been airing in Iowa, opting for a more positive message in the final days before the state's presidential caucus.

The Dean ad labeled his rivals as "Washington Democrats" who voted for the congressional resolution authorizing the Iraq war, while the Gephardt ad questioned his foe's stand on Medicare and Social Security.

The negative ads, which began airing this week and were to end sometime Friday, were risky because Iowa traditionally rewards candidates who stay positive while campaigning.

Dean's only ad that will remain on the air in Iowa is one that began running Thursday in which he asks voters to participate in the caucuses, the first voting of the presidential campaign. Polls show a four-way battle between Dean, Gephardt, John Kerry (search) and John Edwards (search).

Gephardt will continue to run two TV ads: one quotes Martin Luther King Jr., and another says the Missouri congressman will fight against unfair trade policies.

The ad campaigns heated up this week when Dean started running the spot that singled out those three opponents by name as having supported the resolution that authorized the war in Iraq. The ad runs photographs of Gephardt, Kerry and Edwards, including one of Gephardt standing at the White House alongside President Bush and former Senate Majority Leader Trent Lott, a Republican from Mississippi.

"It was a straightforward, honest ad on an important issue," Dean spokeswoman Sarah Leonard said.

On Thursday, Gephardt began airing a commercial that questions how much voters know about Dean. The ad includes clips of Dean talking and asks: "Did you know Howard Dean called Medicare 'one of the worst federal programs ever'? Did you know he supported the Republican plan to cut Medicare by $270 billion? And, did you know Howard Dean supported cutting Social Security retirement benefits to balance the budget?"

"The only reason our spot was ever on the air was because he attacked Dick Gephardt," Steve Murphy, Gephardt's campaign manager, said in a conference call with reporters. "In the waning days of the campaign, we were not going to allow Howard Dean to dictate the agenda."

The Annenberg Political Fact Check (search), a University of Pennsylvania project that checks the accuracy of what politicians say in their ads, said Thursday that Gephardt's ad takes Dean's comments out of context and uses Dean's positions from the mid-1990s and not his current positions.