The answer is identical to the answer to this question:
Is Tom Jones secretly in the closet with Tom Cruise?
Now that we have established that there is only, at most, one Tom in the closet, there are two qualifiers. First, much can happen between now and November, and I don't mind conceding that point. Secondly, this is not a commentary on any of the Republican candidates in GA 12. All of them, as far as I can tell, are likable people who sincerely believe what they profess to believe. They may be right in that their way is the better way forward. But in this district, even in what will be a bad year for Democrats, the likelihood that John Barrow loses this seat is about the same as the likelihood that Helen Thomas will go skinny dipping with Benjamin Netanyahu.
In a perfect Republican world, John Barrow would be extremely vulnerable. The 12th District is located in a fairly conservative part of the country, and Barrow is not a conservative. There have been plenty of times when Barrow has voted with Speaker Nancy Pelosi and the Democratic leadership. Some polls say Ms. Pelosi is the most unpopular politician in the country right now, so all you have to do is say "John Barrow = Nancy Pelosi", right? Um, no. The Republican National Committee, currently suffering under one of its most inept chairmanships ever in the form of Michael Steele (no relation), helped blow a winnable special election in Pennsylvania for John Murtha's old seat by trying exactly that. She may not be a threat for the Miss America crown anytime soon, but most of The People simply don't care about Nancy Pelosi. You may win conservative partisans that way, but then again, you had them at "hel...", much less "hello." Talk incessantly about Nancy Pelosi, and The People will mostly ignore you.
So, you hit on John Barrow's "fake good ol' boy" act, right? He isn't a real Southerner. He calls himself "Barra" to hide his Ivy League heritage. I bet he even went to the Earl "Reel Umureecuhn" Pitts Redneck Accent School so he wouldn't be caught telling The People about how he used to pahk the caah in Hahhvahd Yahhd. Sorry, but that argument is already being propagated by many Republicans (and some Democrats) I know, and that sure helped get 'Barra' defeated two years ago, now didn't it?
"But John Barrow isn't a 'moderate', he's a flaming liberal" you say. Look at how many times he has voted with his party. Whether it's TARP, ze Stimuli, or the GM/Chrysler bailout, "Barra never met a bill that spent taxpayer money that he didn't like" you claim. This actually could cause trouble for Barrow. One of the reasons for the tea party's success is the fact that a lot of people finally got tired of Congress thinking that every problem could be solved by writing a big honkin' check that, in the real world, would be rubbery enough to re-open a shuttered Goodyear plant. Yes, that would be a good argument against Barrow, that is if Republicans didn't have just as bad a record on federal spending as Democrats. It doesn't matter that none of the 12th District GOP candidates were part of that spending problem. All Barrow has to do is pick one or two bills he voted against, highlight those, then remind everyone how Republicans, with the exception of Reagan, historically love to spend their dough, too. He may not win over everyone, but he'll keep at least some of The People on his side.
Not a moderate, eh? "Hello, I'm John Barra, and I voted against Obamacare." It isn't quite checkmate on the "not a moderate" argument, but it's pretty close. When you combine that with a no vote on carbon dioxide regulation to combat "global warming", a yes vote to build a fence on the Mexican border, a yes vote to make the Patriot Act permanent, and a few other votes, you might as well try to argue that John Kerry actually didn't say all those ridiculous things he said, or maybe that he said them before he didn't say them. The GOP will say "but Barrow waits until he gets the word from Pelosi as to whether or not his vote is needed." Even if that is true, it is (a) difficult to prove and (b) matters to The People about as much as soccer matters in the U.S., even if our team does manage to walk on water and win the World Cup (but, with apologies to The Icon Alton Brown, that's another show). As for the argument that Barrow should have taken care of his Democratic base by voting for Obamacare? Barrow knows that if he had voted for the bill, this race would be leaning Republican today.
To be sure, this is a unique year, and as the cliche goes, you never know. But not only does John Barrow have the moderate label in his corner, he has a cool million in the bank to spread that moderate message. Will the Republican candidate get that much coin to compete? It's possible, but right now, I doubt it. There is a reason that none of the political gurus who follow the nation's congressional races have the the Georgia 12th District contest on their radar, other than a few who see it remaining safely in the Democrats' corner. Big national Republican money will only go to those races deemed winnable. It is true that African-Americans, who make up a good chunk of the 12th, may stay home in November, costing Barrow some votes. But will all of the district's independents buy the GOP argument that Barrow is a phony? I could be wrong, but I just don't think so. He won't win in a blowout as he did two years ago. It's possible he may only squeak by, but barring a seismic shift, John Barrow will not be among the legion of Democrats losing their Congressional seats this Fall.