SAVANNAH - The U.S. Chamber of Commerce shelled out $920,000 for TV and online ads promoting Rep. Jack Kingston in the crowded race for Georgia's open U.S. Senate seat.
At the same time, a grass-roots conservative group in neighboring South Carolina spent $515,000 on commercials supporting rival Republican and business executive David Perdue.
Other groups are showering millions more on the fiercely competitive campaign.
Corporations and other special interests are spending big bucks - more than $6 million as of May 8 - to influence the election to replace retiring Republican Sen. Saxby Chambliss. Primary elections in Georgia are Tuesday, with seven Republicans and three Democrats running to advance to the main Senate campaign this fall.
Political action committees representing farmers and retail stores, doctors and drug companies, law firms and ideologues have donated more than $1.3 million to individual campaigns. Outside groups such as the Chamber have coughed up nearly four times that amount to pay for advertising that either endorses or attacks specific candidates.
The high-dollar, big-stakes race is among a dozen with national implications as Democrats look to keep Republicans from taking control of the Senate. Republicans need to gain six seats to claim a majority and can't afford to lose in Georgia. Democrat Michelle Nunn is likely to advance in her primary; the daughter of former Sen. Sam Nunn has proved to be a formidable fundraiser.
With a Republican primary runoff nearly ensured and a heated fall campaign on the horizon, third-party groups invested in Georgia's Senate race will probably open their wallets much wider by November.
Outside groups spent more than $20 million in Georgia when Chambliss sought re-election in 2008. The state's last primary scramble for an open Senate seat, won by Republican Johnny Isakson, was in 2004. That year PACs contributed more than $1 million to GOP and Democratic candidates in the Senate primaries- not far behind PAC donations this year.
It's difficult to compare third-party spending to previous Senate races, in part because court rulings have changed the campaign finance landscape so much. But most campaign leaders and party strategists agree that the phenomenon that's already visible will be more critical in Georgia than it's ever been before, particularly since the seat is so important to determining which party controls the Senate.
Outside groups have focused most of their money, more than $4.6 million, in the Georgia race on advertising.
South Carolina-based Citizens for a Working America PAC spent $1 million attacking Kingston of Savannah as a wasteful Washington spender while putting half that amount into commercials supporting Perdue, a former Reebok and Dollar General CEO.
The Ending Spending Action Fund, founded by former TD Ameritrade CEO Joe Ricketts, pumped $1.75 million into ads accusing Rep. Phil Gingrey of squandering taxpayer money. The group also invested $334,000 in ads attacking Nunn.
In the race that also includes Rep. Paul Broun and Karen Handel, Georgia's former secretary of state, special interests giving directly to the candidates favored Kingston and Gingrey by a big margin.
Gingrey, a physician in Congress for 12 years, reported taking $356,715 from interest groups as of April 30. Some of his biggest donors were doctor PACs, including for the American Association of Orthopaedic Surgeons and the American Association of Clinical Urologists. Gingrey also serves on the House Energy and Commerce Committee and received big checks from political committees of companies that fall under its scope such as Comcast, Exxon Mobile and Wal-Mart.
Special interests poured $365,863 into Kingston's campaign account. He's a longtime member of the House Appropriations Committee, making Kingston an influential voice in how the government spends its money. Broun's appeal to grass-roots conservatives and gun-rights activists shows in his $87,556 from PACs.
Interest groups were stingier to Handel and Perdue, who hold no office. Handel reported $36,850 from PAC donors including Sarah Palin's SarahPAC. Perdue received $18,500 in PAC contributions from seven total groups.
Facing little competition for the Democratic nomination, Nunn has received the most PAC donations of any of Georgia's Senate candidate, raising $475,789 from groups including women's advocates and labor unions.