In tonight’s debate, Mitt Romney made a claim that’s been a GOP talking point for nearly a year: “Oil production is down 14 percent this year on federal land.”

As is typical, this is a completely true statement. Politifraud gives you the numbers in its very fact check. But as is typical for opinion journalists, rather than fact-checkers, they decide that a completely true statement is half-true…just because.

So: Did the United States produce 14 percent less oil on its public lands last year? Yes.

But there’s nuance in the number. Production under Obama was hobbled due to the Deepwater Horizon disaster, making a one-year figure subject to cherry-picking. And it’s not at all clear that the president in charge when the oil is taken out of the ground deserves full credit or blame; years of prior policies on exploration and drilling had an impact.

What’s especially curious about this one is that Politifraud can’t even get its own analysis straight. I mentioned that this has been a GOP talking point for months. Politifact Ohio, run by the Cleveland Plain Dealer, ruled this same statement “Mostly True,” when Sen. Rob Portman said the same thing 7 months ago.

That leaves us here: Portman’s fact was accurate: There was a 14 percent drop on public lands. Everything else can be teased out and spun for either party’s purposes. Under PolitiFact guidelines, when a statement is accurate but needs clarification or additional information, it rates a Truth-o-Meter rating of Mostly True.

When a completely true fact can be rated “Mostly True” or “Half-True,” you’re no longer doing fact-checking, you’re doing opinion journalism.