Stop us if you’ve heard this one: An unpopular Democratic president facing tough economic times overcomes those difficulties to win reelection by pinning the nation’s problems on an obstinate Republican-led Congress.

It’s what President Obama is trying to do these days, and in that way, many see a pretty strong parallel between his 2012 reelection campaign and Harry Truman’s 1948 reelection bid.

President Harry Truman and wife Bess smile from rear platform of their special train as they leave on Nov. 26, 1949, in Washington to attend the Army-Navy football game in Philadelphia. (AP Photo)

But the “Obama equals Truman” comparison also misses the point in some major ways.

Yes, Truman was broadly unpopular for much of his first term. And, arguably even more than Obama, he had to deal with a bad economy, including rationing after World War II and a national debt that had many calling for austerity measures. Truman was also coming off a midterm election in which the American people delivered his party a strong rebuke, and appeared headed for another defeat.

But Truman also had a lot going for him: most notably an economy that was recovering by the time voters went to the ballot box in November 1948.

Critics of the Obama-as-Truman meme point out that Truman had strong growth in the three quarters leading up to his reelection — more than 6 percent, according to the Bureau of Economic Analysis. That was a vast improvement over the negative economic growth the Truman Administration had experienced in the two preceding quarters in 1947.

And, as the economy recovered, so did Truman’s approval rating. Gallup didn’t measure his approval in the runup to the election, but it rose from 36 percent in April 1948 to 69 percent in January 1949, just after he won reelection.

“Truman’s come-from-behind win and is really not applicable in this case,” said James E. Campbell, a presidential historian at the University of Buffalo. “The economy in 1948 as they were heading into the election was really booming.”

Obama, by contrast, has seen few tangible signs of a turnaround and, in the minds of many, the economic picture is actually getting bleaker.

Still, some argue that the economic progress made in 1948 wasn’t quite so evident at the time — making the idea that Truman won because of an improving economy ring false.

Zachary Karabell, the author of “The Last Campaign: How Harry Truman Won the 1948 Election,” notes that the Gross Domestic Product was a relatively new measure at the time, and that peoples’ perceptions of the economy were much more about how it appeared in their everyday lives.

“The number had just been invented,” Karabell said. “It’s just like how nobody really knew what was going on during the Great Depression. I think those comparison are problematic and spurious that president only gets elected when there is ‘X’ growth.”

At the same time, even Karabell concedes there are differences.

For one, Republicans controlled all of Congress in 1948, but they control only the House today. That could muddle things as Obama seeks to blame Congress.

Karabell also notes that the tone Truman used against Republicans was much harsher. Truman even called the GOP Congress back into session in August 1948 (in a steamy chamber without air-conditioning, no less), demanding that they pass his agenda.

“The one thing that’s not so encouraging if you’re Obama, is that Truman really campaigned against Congress emphatically,” Karabell said. “The rhetoric of Truman and [Franklin Delano] Roosevelt against the moneyed classes was so much more virulent than anything we talk about today.”

We’ll keep an eye on how Obama escalates his rhetoric – if he does – but the Truman rhetoric of the 1940s may not play so well in today’s media environment. (Think “Give ‘em hell.”)

More than anything, the differences between 1948 and 2012 prove that no two elections are completely analogous. If Obama’s going to win a second term, he’s got to do it in his own way.

While there may be lessons to learn from Truman, the biggest lesson might be that a recovering economy cures all ills. Truman had it, and if Obama somehow managed to get it, his electoral prospects would brighten too.