It all seemed to be breaking the right way for Rep. Jack Kingston after the Senate Republican primary. Kingston was able to hold off a late surge by Karen Handel in the primary campaign’s closing days to make it into a runoff with businessman David Perdue, the frontrunner.

Kingston then started hauling in endorsements from candidates like Handel and Rep. Phil Gingrey, along with the support of House colleagues Lynn Westmoreland, Tom Price and Rob Woodall. Former House speaker Newt Gingrich also said he was supporting Kingston in the runoff. Those endorsements were followed by independent polls showing Kingston with a double-digit lead over Perdue as the candidates trudged towards the July 22 runoff.

But that all changed after a story broke in the Atlanta media about more than $80,000 in Kingston campaign contributions that were connected to a convicted felon facing possible deportation. Kingston received the contributions from various people associated with two Gwinnett County companies linked to Khalid Satary, a Palestinian who served more than three years in federal prison for running a counterfeit CD operation. Ever since his release from prison in 2008, the federal government has been trying to boot Satary out of the country.

Kingston’s campaign has not denied accepting the contributions—that would be difficult to do considering that Kingston was photographed at a fundraiser with Satary. However, the congressman has yet to come up with a coherent explanation as to why his campaign would have even accepted money from such questionable sources in the first place. Unable to explain itself, the Kingston campaign has fallen back on a time-tested political tactic: Blame the media. Kingston’s spokesman says these “baseless attacks” by reporters are part of a “smear campaign” being waged against the congressman.

The story of the mysterious contributions from a convicted felon does not seem to have had an impact in any runoff polls, but the uproar did provide an opening for Perdue to go after his runoff opponent. “Any campaign can have rogue contributors—that happens,” Perdue said after the story first broke.

“It just raises questions,” Perdue said. “Why did they keep the money then if they think it’s appropriate to give it back now, and why did they cover it up for two months? I think the voters of Georgia would like an answer to that question.” To make up ground in the runoff, Perdue may have to ask those same questions in campaign commercials that keep the issue alive with Georgia voters. There are many advertising consultants who could take the basic facts of the Kingston story and come up with a dozen attack ads right off the top of their head.

Perdue has the financial resources to take that line of attack, if he chooses. He and Kingston have both raised credible amounts of money for the Senate race. The last available campaign reports showed Kingston had raised $5.62 million, a total that included $1.9 million he transferred from his U.S. House campaign account. Perdue had raised $4.34 million, with about $2.65 million coming out of his own pocket. As the wealthy, retired CEO of several large corporations, Perdue would be able to write one more large check to his campaign for one last push in the runoff campaign.

Is he willing to do that? When I raised the question in a recent interview, Perdue did not give a definitive answer.

“We will have the resources to get our message out,” was all he would say. “I’m a business guy—I put serious skin in the game.”

That may be the decision on which this Senate runoff hinges. Is Perdue willing to go all out in one last surge against Kingston? Or can Kingston hang on to enough of his polling lead to run out the clock and get the nomination?