As the Associated Press notes, Griffith has spent $255,000 of his own money on the primary. Pre-primary FEC filings covering the race up through May 12 show that Griffith's campaign spent a total of $1.1 million. By comparison, Brooks had spent only $137,000, and Phillip spent under $700,00.
Griffith was elected to a Democratic-held open seat in 2008, winning a 51%-49% race in district that John McCain carried by a margin of 61%-38% over Barack Obama. He switched parties in 2009, citing the health care bill and Democratic spending as a major reason. He had voted against all the big-ticket items of the Democratic agenda that year, including the stimulus, cap-and-trade and the health care bill.
Jess Brown, a political science professor at Athens State University, explained to the AP that many local Republican voters still remember Griffith's 2008 race. "That congressional race was a bloodbath. A lot of hard-core Republicans worked hard for [Republican nominee] Wayne Parker," Brown said. "When Republican activists talk to me, I sense they haven't accepted Parker Griffith."
Along with the example of Pennsylvania Sen. Arlen Specter, who lost his Democratic primary last week after switching from the Republican Party in 2009, we should get a further data point next week of whether primary voters are willing to nominate a party-switching incumbent.