The polls continue to show Nathan Deal and David Perdue with relatively small but stubborn leads over their respective Democratic challengers, Jason Carter and Michelle Nunn. But Nate Cohn, analyzing data in The Upshot for the New York Times, suggests today that the actual margins may be even tighter than the polls are telling us.

Why?

Because "no other plausibly competitive state has seen a more favorable shift for Democrats in the racial composition of eligible voters over the last decade," and pollsters haven't quite kept pace with that change, Cohn writes.  Citing data from the Georgia secretary of state's office, he points out that the white share of registered voters has fallen by more than four percentage points just since 2010. White voters comprised 62.6 percent of registered voters four years ago; they comprise 58 percent today.

In a tweet earlier this week, Cohn pointed out another number that I found startling: "Since Nov 2013, the number of white registered voters in GA has increased by 84,582. Nonwhite: 125,446." At a pace like that -- 40 percent white, 60 percent nonwhite -- it doesn't take long to create a new electorate. By 2016, the impact could be profound.

But after making various adjustments for turnout, etc., what's the upshot of Cohn's analysis for 2014?

".... polls show Mr. Perdue ahead by 3.3 points, but they would show something closer to a dead heat if the likely electorate matched my estimates."

To complicate the picture still further, the AJC's Kristina Torres reported this week that the surge of new voter applications -- unusual in a midterm election -- has pretty much overwhelmed the system, with perhaps tens of thousands of applications yet to be processed and early voting scheduled to begin on Monday.

"We're aware of the many voters still in pending status," said Harvey, who on Tuesday urged residents who believe they properly registered to contact their county election office to confirm their voting status."

Publicly, Secretary of State Brian Kemp has tried to focus public attention on fraudulent applications -- now reportedly up to a whopping 50 out of more than 85,000 submitted in a registration drive by the New Georgia Project. But with so many legitimate applications yet to be processed, there's a growing fear that thousands of Georgians who are eligible to vote and have registered to vote may not be able to do so.

Maybe it's just me, but it seems pretty clear which problem poses the greater threat to the sanctity of the ballot.

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UPDATE:

I should add that as polls roll in, they continue to document just how heavily the Georgia GOP depends on support from those 65 and older, which cannot bode well for the party in the long term. Or even medium term, as time takes its inevitable cruel toll.

For example, here's the age breakdown in the new PPP poll. It shows Perdue up by two points overall, but without the overwhelming, 25-point lead that he enjoys among older voters, it would be a very, very different story:

Another new poll --

-- but the same basic result. Perdue has a four-point lead, but only because of a huge, 28-point advantage among those 65 and older: