Here is a funny thing to contemplate: if Barack Obama were running in the current election, he’d probably win a third term. His most recent job approval rating of 54 percent is one of the highest for a president before the election since modern polling began. It also suggests that he is far more popular than the two major candidates to succeed him, both of whom have strong negatives. The only problem, of course, is a bit of the constitutional text that prohibits him from running, namely the 22nd amendment, which limits the president to two terms.

Term limits are of ancient origin and date back to the ancient Greeks. The American founding fathers thought about adopting term limits for the presidency in our foundational text, but declined to include them. Constitutional silence on the matter, however, did not prevent an informal norm from emerging. George Washington left office after two terms and set a precedent that would be followed by the next thirty presidents, including some, such as Thomas Jefferson and Andrew Jackson, who could easily have won a third term. As early as 1839, John Quincy Adams was calling the two-term limit a “tacit subsidiary constitutional law.” Later in the nineteenth century, when President Ulysses S. Grant was considering running for a third term, a popular outcry declared the rule to be an unwritten constitutional norm.

The scope and limits of this unwritten norm, however, became an issue when Theodore Roosevelt sought to run on his independent Bull Moose ticket in 1912. Roosevelt had succeeded to the presidency in 1901 after the assassination of William McKinley in 1901, and had served through 1908 after winning his own election. He then decided not to run again, but four years later changed his mind. During the 1912 campaign, Roosevelt was shot by a madman who justified his actions on the grounds that two terms was the maximum allowed. (Roosevelt finished his speech before seeking medical care, but didn’t win the presidency.) The 1912 winner, Woodrow Wilson, made noises about a third term in 1920, but was too unpopular to have a chance at it.

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