Super PACs dominate Republican primary spending South Carolina voters are being buried this week under an avalanche of combative and often nasty political commercials from super PACs, funded by a tiny group of super-rich donors with very particular interests in the state's Republican primary. Hedge-fund king John Paulson, who donated $1 million to a group backing former Massachusetts governor Mitt Romney, would very much like to see President Obama's financial reforms repealed. The Marriott brothers, who also gave $1 million to a pro-Romney super PAC, have lobbied Washington for favorable tax and immigration policies through their hotel companies. Explore the candidates" campaign finances And casino magnate Sheldon Adelson recently dashed off a $5 million check to a group backing former House speaker Newt Gingrich, marking what may be the largest single political contribution in U.S. history. Adelson is well known for supporting hard-line policies favoring Israel while also advocating measures that would benefit the gambling industry. "There are probably fewer than 100 people who are fueling 90 percent of this outside money right now," said David Donnelly, national campaigns director at the Public Campaign Action Fund, an advocacy group favoring limits on political spending. When you think about the amazing impact that this small number of people have on deciding the election, on the information that people will have on who to vote for, it's mind-boggling. The departure of former Utah governor Jon Huntsman Jr. from the field on Monday also underscores how few rules govern super PACs, which are free to shift their support and money to another candidate or cause once their main beneficiary bows out. A group called Our Destiny PAC spent $2.5 million backing Huntsman, bankrolled in part by his billionaire industrialist father; its future plans are unclear. In total, these new and unrestrained political action committees spent more than $15 million supporting GOP candidates in Iowa and New Hampshire and are now outspending the official campaigns in South Carolina by 2 to 1, according to advertising and expenditure data. The onslaught of outside money has already shaped the contours of the race, shoring up Romney in Iowa and giving candidates such as Gingrich (Ga.), former senator Rick Santorum (Pa.) and Texas Gov. Rick Perry a last chance to break through in South Carolina. Sporting anodyne names such as Endorse Liberty and Make Us Great Again, super PACs are taking advantage of recent court rulings allowing corporations, unions and wealthy individuals to spend as much as they want on elections. The groups have quickly evolved into de facto shadow operations of the traditional campaigns, despite rules forbidding direct cooperation between the two. Super PACs are generally staffed by former aides of the candidates they support, and they are fueled by benefactors wealthy enough to write six- and seven-figure checks for what amounts to a political gamble. The biggest super-PAC donors also are often fundraisers for the candidates: A Wall Street event for Romney on Tuesday includes at least six hosts who gave to the main pro-Romney super PAC as well.