By Bill Barrow & Christina Cassidy - July 27, 2014

ATHENS, Ga. (AP) -- Republicans are on the offensive in the opening days of Georgia's Senate campaign, hammering Democrat Michelle Nunn as a rubber stamp for President Barack Obama and questioning her resume as a non-profit executive - the very experience that anchors her appeal as a moderate who gets things done without partisan wrangling.

It's a preview of a high-profile clash between two first-time candidates, Nunn, 47, and former corporate executive David Perdue, 64, with the outcome helping to decide which party controls the Senate for the final two years of Obama's presidency.

Nunn is one of the Democrats' few hopes to pick up a GOP-held Senate seat as they try to hold their majority and establish Georgia as another Southern swing state alongside Virginia and North Carolina. Republicans need six more seats to run the chamber and know they can't afford to let Nunn succeed retiring Sen. Saxby Chambliss. There's also a little-known Libertarian on the Nov. 4 ballot.

Both sides agree that with no sitting politician left in the race, Nunn and Perdue will clash over personalities and backgrounds as they try to capitalize on voter discontent. They're trying to energize their core partisan supporters even as Nunn, especially, focuses on independents.

Perdue now sounds a more partisan tone after spending months blasting Rep. Jack Kingston and two other sitting congressmen as being part of the problem in Washington. Fresh off defeating Kingston in a primary runoff, Perdue promised to "prosecute the failed record of the Democratic administration over the last six years."

He urged Georgia voters not to give Senate Majority Leader Harry Reid "one more vote" in the chamber and called for the repeal of Obama's health care law and the Dodd-Frank law that changed financial regulations after the 2008 market collapse. Earlier in the year, Perdue said he wanted to work with Democrats to amend Dodd-Frank, not repeal it. And as a business executive, he once said that it would take a federal solution to reduce the number of uninsured Americans.

Meanwhile, a conservative Super PAC launched a television ad telling voters that Nunn supports "Obamacare." The ad also notes that she presided over layoffs when one of her earlier foundations merged with former President George H.W. Bush's Points of Light organization. Ending Spending Action Fund, the conservative political action committee, is backed by Joe Ricketts, founder of TDAmeritrade and owner of the Chicago Cubs baseball franchise.

Nunn uses those attacks to tie Perdue to her usual critique that "our political system is broken."

Even more pointedly, Perdue dismissed Nunn's experience running Points of Light. Perdue argues that her post at the foundation does not prepare her for tackling issues in the free-enterprise system. His own background is in for-profit firms such as Reebok, Dollar General and the failed textile company Pillowtex.

Nunn has echoed criticisms that Perdue weathered from his Republican rivals, namely that he presided over layoffs and outsourcing. "My record, obviously, is around building communities, lifting people up, trying to make a difference, working in collaboration with folks from the other side," said Nunn, whose father, Sam, represented Georgia in the Senate for 24 years.

She has a tough contest on her hands. She's running in a state Obama lost twice - even if by much closer margins than the rest of the Deep South. And now Perdue's victory over Kingston takes away her opportunity to continue her "outsider" campaign against an 11-term congressman.

Nunn treads lightly on her party affiliation. Her ads don't mention she's a Democrat. She talks repeatedly of "moderation," noting the word is part of the Georgia state motto: "Wisdom Justice Moderation."

Yet she's voiced support for a path to citizenship for people in the U.S. illegally, in a recent nod to liberals she has often avoided, even while calling for tighter border security.

Democrats say Nunn can succeed with a campaign that mixes her arguments about Washington's ineffectiveness with direct attacks on Perdue's record.

At the Democrats' national Senate campaign office, spokesman Justin Barasky skewered Perdue for "a record of tearing apart companies and communities by slashing thousands of jobs." Georgia Democratic Party Chairman DuBose Porter compared Perdue to Mitt Romney, whose wealth became a liability for the 2012 Republican presidential nominee.

Perdue said that doesn't worry him: "Well, I have lived through about six months of that. How'd that work?"