Super PACs now a force in the presidential race

Smith said Solutions 2012 could potentially launch negative attacks on the other candidates if necessary.

"Newt has been focusing on being positive and, if possible, we want to stay positive," Smith said.

Other super PACs have also started to make their mark on the presidential contest.

Priorities USA Action, which supports Obama's re-election bid, launched an ad on Iowa cable stations Thursday advocating a tax increase for millionaires. The group, headed by two former Obama White House aides, has spent $148,000 since early November, mostly on Web and TV ads bashing Romney.

Crossroads GPS, by far the largest and most influential super PAC during the 2010 midterm elections, has said it would get involved in the presidential race during the general election. But the group has spent $300,000 in Iowa targeting Democratic Rep. Leonard Boswell for supporting Obama's health care overhaul, making the group's criticism of the president part of the political conversation in the weeks leading up to the caucuses.

Crossroads is expected to further ramp up its attacks on Obama's record in coming weeks.

Associated Press writer Jack Gillum in Washington contributed to this report.

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