It's no secret that Nathan Deal wasn't the first choice of a successor for Georgia Gov. Sonny Perdue.
Though Perdue is probably happier with his fellow Republican winning on Tuesday than he would have been with a victory from Democrat Roy Barnes -- the man Perdue sent packing in 2002 -- Perdue's first choice as a successor was Karen Handel.
But whomever it was to be, the next governor will have the current inhabitant of the Govrnor's Mansion to thank for one piece of bad news.
It hasn't happened yet. But it will. Perdue saw to that last week. Perdue traveled to several schools to trumpet what he claims is a huge gain in the state's high school graduation rate, up 17 percentage points during the past seven years.
The timeline, obviously, was calculated to portray Perdue as having improved graduation rates since he booted Barnes from the governor's office.
More importantly, though, the announcement set a time bomb for Perdue's successor, who we now know is Deal.
It's a time bomb because Perdue knows not only that his claim of huge improvements in the graduation rate is based on smoke and mirrors, but he knows it will disappear next year when the state uses a more honest assessment.
Georgia currently calculates its graduation rate with what's called the "leaver rate."
Notoriously unreliable, the "leaver rate" is what allows Perdue to claim 80.8 percent of the state's high schoolers graduate.
The EPE Research Center, a nonprofit organization that publishes Education Week, counters that a more reliable figure is less than 60 percent.
Georgia State School Superintendent Brad Bryant says this is the final year Georgia will use the "leaver rate." Along with other states complying with federal No Child Left Behind criteria, Georgia next year will switch to the "cohort" method.
As a result, the Atlanta Journal-Constitution reports the state department of education already is preparing for what is expected to be a "significant" drop in the graduation rate.
But that drop won't come during Perdue's term. Nope. That time bomb is set to explode during Deal's term. Mark it down now.
We know how ugly this year's gubernatorial election has been. Just wait until four years from now, when a challenger is accusing Deal of presiding over "plummeting" graduation rates.
Perdue will be laughing all the way to retirement.