By Alina Selyukh and Alexander Cohen
WASHINGTON (Reuters) - A U.S. campaign finance watchdog on Monday officially challenged the legality of a presidential election campaign ad aired by a pro-Mitt Romney "Super PAC," calling for an investigation by the Federal Election Commission.
The non-profit, non-partisan Campaign Legal Center filed a complaint alleging a violation of campaign finance rules by Restore Our Future, the political action committee supporting Romney as a Republican presidential nominee.
The Super PAC last week launched a new ad that is nearly a carbon copy of another TV spot that Romney's campaign aired in his failed 2008 bid. The ad aired in Arizona and Michigan, where the Super PAC has spent almost $3 million on advertising.
Super PACs can raise and spent unlimited amounts of money but cannot coordinate with candidates.
By sponsoring a re-airing of the ad originally made for the Romney campaign, Restore Our Future violated FEC regulations by effectively making a contribution to the campaign, and one that also exceeds the $2,500 donation limit, according to the Campaign Legal Center's lawyer Paul Ryan.
"Super PACs are prohibited from contributing to candidates," Ryan said in a statement. "The airing of these ads constitutes a clear violation of federal law by the shadow campaign committee Restore Our Future."
Super PACs, and especially the pro-Romney one, have triggered a spending free-for-all the campaign season leading up to the November 6 general election.
They have funneled nearly $60 million into the presidential race. Spawned by a 2010 Supreme Court decision, these groups have been driving the Republican nominating contest haywire with negative ads.
Restore Our Future's ad in question shows Romney's former business partner Robert Gay telling the tearful story of the search for his teenage daughter who had gone missing. Romney at the time shut down his firm, Bain Capital, and brought dozens of his employees to New York City to help find the teenager.
The original ad, produced by Larry McCarthy who now works for Restore Our Future, differs from the new version only with a couple of older photos and the signoff that says "I'm Mitt Romney and I approved this message."
The Super PAC, run by former Romney staffers, argued that the reuse of the ad was legal because the group bought the rights to the footage from a third-party owner, "which did not entail interacting with the Romney campaign," according to the group's treasurer Charlie Spies.
By law, submitted complaints trigger an examination by the FEC. Such investigations, however, often take years to complete and rarely lead to more than a fine.
Besides, the future of Super PACs is even murkier.
"That's the beauty of these Super PACs," said campaign finance expert Rick Hasen, professor of law at the University of California, Irvine. "They are unaccountable and will disappear after the election. Any complaint won't get decided before the election."
To read the complaint filed to the FEC, please see http://r.reuters.com/nyw76s
(Additional reporting by Alexander Cohen. Editing by Alistair Bell and Christopher Wilson)