DES MOINES, Iowa – The attacks began three weeks ago and have not let up since: Television ad after ad slamming Newt Gingrich for having "more baggage than the airlines," for being fined by Congress for ethics violations, for his position on illegal immigration, even for admitting that he has made mistakes on the campaign trail.

Democrats and Republicans alike have singled out the $2.8 million-and-counting TV ad campaign as the biggest factor in Gingrich's precipitous drop in polls of Iowa voters and Mitt Romney's corresponding rise.

The ads, which continue to blanket Iowa days before the caucuses, were created and paid for by people with deep knowledge of the Romney campaign's strategic thinking, close relationships with Romney's most generous donors, and even research on what television viewers like and dislike most about Romney himself.

Yet neither Romney nor his staff has had to lift a finger or spend a dollar to make it happen. In a stark illustration of how last year's landmark Supreme Court ruling on campaign finance has created new channels for outside money to influence elections, the negative onslaught is the work of a group called Restore Our Future.

The most prominent of the "super PACs," which can accept unlimited donations for purposes of supporting or attacking candidates, it operates independently of the Romney campaign but under the direction of former Romney aides who do not need to be told what the candidate needs.

They include Carl Forti, the political director of Romney's 2008 campaign; Charles Spies, Romney's former chief counsel; and Larry McCarthy, an alumnus of Romney's media team who was known for producing some of the more compelling positive spots for Romney four years ago but has nonetheless earned a reputation as one of the most fearsome political ad makers in the country – he produced the Willie Horton commercial that devastated former Gov. Michael Dukakis' presidential campaign in 1988.

Restore Our Future's fundraiser, Steve Roche, led the Romney campaign's own finance team until this summer. He now spends his days meeting with the New York hedge fund managers, Utah businessmen and Boston financiers who have contributed almost $30 million to the group this year, said people with knowledge of the group's fundraising. Among the donors are some conservatives who have a long history of backing attack-oriented outside groups like Swift Boat Veterans for Truth, which in 2004 went aggressively after Sen. John Kerry, the Democratic presidential nominee that year.

The result: Romney has effectively outsourced his negative advertising to a group that has raised millions of dollars from his donors to inundate his opponents with attacks – all without breaking the rules that forbid super PACs to explicitly coordinate with candidates.

Polls showed Gingrich's support in Iowa tumbling immediately after the Restore Our Future ads began running in early December. An NBC News/Marist poll released Friday showed a 19-percentage-point increase over the past month, to 35 percent, in the number of likely Republican caucus-goers who said they judged Gingrich to be unacceptable as the party's nominee.

Since they began advertising in earnest several weeks ago, groups like Restore Our Future have spent millions of dollars in the early primary states, rivaling and in some cases surpassing the spending of the actual candidates.

While the candidates can raise just $2,500 from each individual donor for the primary, super PACs, thanks to the Supreme Court's Citizens United decision, face no such restrictions.

Speaking on Fox News last week, Romney played down the significance of Restore Our Future's advertisements against Gingrich, arguing that Gingrich was falling in polls as voters focused on his record. Gingrich has also been under intense assault from other groups, including Ron Paul's campaign; Romney's campaign itself called attention to Gingrich's tumultuous departure from Congress in a mailing it sent to Iowa voters.

In recent days, Romney has tried to distance himself from the group. "We really ought to let campaigns raise the money they need and just get rid of these super PACs," Romney said on MSNBC.

But in July, Romney appeared before dozens of potential donors to Restore Our Future at an organizational meeting, effectively blessing its work.

© Copyright The Sacramento Bee. All rights reserved.