But a close look at the results seems to indicate that geography more than ideology--and far more than big-name endorsements, may have influenced the results, and could be determinative in the runoff.
Nathan Deal represented North Georgia's 9th congressional district in the House for eighteen years (the first three as a Democrat). Before her election as Secretary of State in 2006, Karen Handel chaired the Fulton County (Atlanta) Commission. So you'd figure that Deal would do pretty well in the 9th and Handel would have an advantage in Atlanta.
That turned out to be very true. According to my own calculations (see this nifty results map from the Atlanta Journal-Constitution), in a field with four viable statewide candidates, Deal won all but one county in the 9th, and took 46% there overall. In the 26 metropolitan Atlanta area counties that are not in the 9th district, Karen Handel won 39%.
In looking at the impact of big-name endorsements, it should be noted that Newt Gingrich's home county, Cobb, is in metro Atlanta, and also happens to have cast more Republican primary votes than any other of Georgia's 159 counties. It does not appear Newt was able to do much for Deal: Handel won 41% in Cobb to 20% for Deal, who was actually edged out for second place by Eric Johnson.
How do things look for the runoff? Well, Deal's lucky that 9th district congressman Tom Graves, who won the seat in a special election (and runoff) after Deal resigned, was narrowly knocked into another runoff by the same candidate he beat previously, Lee Hawkins. So turnout in the 9th will be relatively high.
But in metro Atlanta, Handel's stomping grounds, there's a hot congressional runoff in the heavily Republican 7th district, centered on Gwinnett County, where Handel beat Deal 38-23 in the primary. (There's also a Republican runoff in the Atlanta-area 13th district, though not a lot of Republican voters there.)
Now it would be easy to say that with Deal being strong in North Georgia and Handel strong in Atlanta, the runoff will be determined by the rest of the state. And that seems to be the take offered by the Atlanta Journal-Constitution:
Analysis of Tuesday’s primary showed that the candidates both played to their constituencies and triumphed in their strongholds – Handel in metro Atlanta and Deal in Northwest Georgia. But voting patterns also showed that to win the Aug. 10 runoff, one of the candidates will have to forge a coalition with downstate rural and Savannah.
The analysis goes on to suggest that Savannah-based third-place finisher Eric Johnson could make a huge difference with his endorsement, if he makes one.
That could be true, but there are three other factors that make Handel the strong favorite no matter what Johnson does. First, her Atlanta area base represented almost exactly half the statewide Republican vote, while Deal's 9th district accounted for only 13%. Second, Handel did better in Deal's home ground than Deal did in hers: Handel won 26% in the 9th, winning one big county (Forsyth) and finishing second everywhere else, while Deal won only 16% in metro Atlanta. And third, in the rest of the state, which accounted for 36% of the statewide vote, Handel won 32% while Deal won only 24%. In fact, in Eric Johnson's southeast Georgia base, Deal was in single digits in most counties, and won only 4% in the biggie, Chatham (Savannah). Handel managed to win 14% even there, and generally showed a statewide appeal.
Endorsements by other candidates could matter. Perhaps Gingrich or Palin will kick out the jams and get really active, or other presidentials could weigh in (Handel's already been endorsed by Mitt Romney for the runoff). And maybe Deal's efforts to position himself as the "true conservative" in the race, with an intensive emphasis on immigration and with help from the state's anti-abortion lobby, which has been feuding with Handel, will make a big difference in a low-turnout contest. And who knows, it's conceivable that Handel's support for abolition of the state income tax will get her in trouble given the state's very serious budget problems.
But at this juncture, geography seems to have been the key to Tuesday's results, and should matter most on August 10.
UPDATE: As Harry Enten notes over at pollster.com, the four polling firms in the field (Insider Advantage, Mason-Dixon, Magellan Strategies and Rasmussen) during the final week of the Republican gubernatorial primary did a good job of picking up late surges by Handel and Johnson and the fatal swoon by long-time front-runner John Oxendine. Given the instability of the race, and the traditional difficulty of polling southern primaries, congrats are in order. It will be interesting to see if they venture back out for the runoff.