An unprecedented amount of corporate cash is flooding into the Republican presidential race, fueling a barrage of attack ads that bloodied several candidates before Barack Obama could even step into the ring.
A 2010 U.S. Supreme Court ruling that granted corporations and labor unions the freedom to spend unlimited amounts of money on campaign ads has opened the door to so-called super-PACs, political action committees that can raise as much money as they want as long as they don't directly coordinate their attack ads with the campaign they're supporting.
The independence of such operations is murky at best, however, since many super-PACs are run by people with close ties to the candidates they support.
A super-PAC backing former Utah Gov. Jon Huntsman is led by his father. A pro-Obama super-PAC, Priorities USA, is stacked with the president's former aides.
The majority of super-PAC funding has been spent on attack ads, allowing candidates to deny responsibility for bloodying their opponents and avoid any blowback those attacks may generate among voters.
Republican presidential candidate Newt Gingrich may be the first victim of super-PACs.
Gingrich's support was surging in early December when Restore Our Future, a super-PAC backing Mitt Romney, aired a spate of negative ads against the former House speaker that sent Gingrich's poll numbers plummeting.
Meanwhile, Romney deftly distanced himself from the ads by noting that Restore Our Future is not an extension of his campaign.
After criticizing Romney for unleashing an attack-dog PAC, Gingrich responded with a super-PAC of his own, Winning Our Future, which was funded by a $5 million contribution from casino mogul Sheldon Adelson. Gingrich's super-PAC is now peppering South Carolina voters with ads portraying Romney as a ruthless financial tycoon.
"This is going to be Armageddon -- they are going to come in here with everything they've got, every surrogate, every ad, every negative attack," Gingrich said on CNN, defending his engagement in the super-PAC "war."
Super-PACs have so far poured more than $9 million into advertising just in South Carolina, which votes Jan. 21. Romney's Restore Our Future this week bought $3.4 million in TV ads in Florida, which votes Jan. 31.
Some Republicans worry that the intraparty super-PAC attacks will weaken their eventual nominee.
"On the flip side of that coin, many of the same attacks will be used by Democrats as well, so getting them out now may inoculate a candidate from the full weight of those attacks later," said Republican strategist Matt Mackowiak.
Sen. John McCain, R-Ariz., a former presidential candidate and one of Capitol Hill's most outspoken critics of super-PACs, lashed out against unlimited donations aiding political campaigns, saying they invite corruption and scandal. He called the Supreme Court decision that gave rise to super-PACs "one of the worst decisions ever seen."
By contrast, supporters of super-PACs say the committees facilitate political debate and help level the campaign playing field.
Former Pennsylvania Sen. Rick Santorum had just $22,000 to spend in Iowa and he couldn't afford to buy any air time. But days before Iowa voted, a super-PAC spent more than a $500,000 on pro-Santorum ads.
Santorum finished just eight votes behind Romney in Iowa. Santorum's PAC has so far spent twice as much in South Carolina.