CNN’s Candy Crowley made a noteworthy comment on the air last night, and we’ve heard similar remarks from other media figures quite a bit lately. The subject was President Obama’s prospects for a second term.

“He has to buck history, number one, a president with that kind of high unemployment rate has never been re-elected at 9 percent.”

At first blush, the observation is plainly false. Franklin Delano Roosevelt won a second term when unemployment was at 17%.

In fairness, though, Crowley probably just misspoke, and meant to refer to the post-Depression era. But even if we give her the benefit of the doubt here, the observation is largely pointless.

As a factual matter, it’s true that every president since FDR who’s won re-election has seen an unemployment rate below 7.2%. Will the unemployment rate fall below 7.2% by Election Day 2012? No one, anywhere, believes this is even remotely realistic.

But the context matters, and the media routinely pretends it doesn’t exist. No president since FDR has won with a high unemployment rate because no president since FDR has had to govern at a time of a global economic crisis like the Great Depression or the Great Recession. The U.S. has seen plenty of downturns over the last eight decades, but financial collapses are fairly rare, produce far more severe conditions, and take much longer to recover from.

Of course the unemployment rate won’t be below 7.2%. Under the circumstances and given the calamity Obama inherited, that’s impossible.

The more relevant question is what Americans are willing to tolerate and consider in context. In 1934, during FDR’s first midterms, the unemployment rate was about 22%. The public was thrilled — not because a 22% unemployment rate is good news, but because it had come down considerably from 1932. By 1936, when FDR was seeking re-eleciotn, the unemployment rate was about 17%. How can an incumbent president win re-election with a 17% unemployment rate? Because things were getting better, not worse.

That’s obviously the challenge for President Obama. The numerical thresholds are largely irrelevant — comparing the current economic circumstances to what other modern presidents have dealt with is silly. The more relevant metric is directional — are things better or getting worse by the time voters head to the polls, and if worse, who gets the blame.

What’s more, let’s also not lose sight of sample sizes. CNN’s Crowley made it seem as if no American president has ever won a second term with this high an unemployment rate. But even if we limit the analysis to the post-FDR era, as Dana Houle explained a couple of months ago, “Since FDR only Eisenhower, Nixon, Carter, Reagan, Clinton and the two Bush’s have been elected president and then sought reelection. It’s hard to draw big conclusions from a sample of seven.”

If the media is preoccupied with this metric, it will shape the public’s perceptions and help drive the campaign. Here’s hoping news outlets come to realize how incomplete this picture is.

Our ideas can save democracy... But we need your help! Donate Now!

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.