Second terms are jinxed, at least in the U.S. presidency. So one might conclude, watching President Obama stumble through the Obamacare rollout of 2013 — then remembering the troubles of Presidents W. Bush, Clinton, Reagan, Nixon and Truman during their second stints in the White House.

The pattern holds, but not as tightly, among Minnesota governors. Tim Pawlenty's too-obvious presidential ambition grated on Minnesotans in his second term. Rudy Perpich wore out his welcome so badly in his second full term that voters turned him out in 1990. Wendell Anderson took himself out during his second gubernatorial term to serve in the U.S. Senate, from which voters ejected him two years later.

What gives with second terms? And if they carry structurally inherent risks, what can be done to minimize the dangers?

Those questions were excellent excuses last week for calling Richard Moe. He's a genial native Duluthian, a former vice presidential chief of staff, a former head the National Trust for Historic Preservation, and an able historian whose new book qualifies him as an authority on the terms of executive officers in American government.

The book is "Roosevelt's Second Act: The Election of 1940 and the Politics of War," and it's a dandy look at the one time in U.S. history when a president sought and won a third term.

Franklin Roosevelt went on to win a fourth term, too, of course. But that story must wait for a sequel. Moe's new tome is confined to the personalities and drama of 1939-40, when Nazi and Japanese appetites to control entire continents sparked the start of World War II.

Roosevelt's belated decision to run again in 1940 is history that won't be repeated — not without constitutional change, anyway. The post-Rooseveltian 22nd Amendment to the U.S. Constitution says it's two-and-done for U.S. presidents.

For a term-limit skeptic like me, the advisability of that amendment has always been in doubt. Wouldn't a second-term president be less likely to run afoul of popular opinion if he/she at least had the legal option to run a third time? Wouldn't that possibility tamp down the temptation to indulge some typical second-term foibles — hubris after a second win, arrogance in the solo exercise of power, excessive zeal in pursuit of a personal agenda?

Moe countered well: Roosevelt was unconstrained by term limits, yet he succumbed to those very impulses during his second term. It was so bad that FDR might have originated the concept of a second-term curse, Moe allowed. (Abraham Lincoln and William McKinley might note that they encountered a more deadly variant of the curse, much earlier.)

Roosevelt's mistakes from 1937 to 1939 make the Obamacare website glitches look like typographical errors. Roosevelt backed off federal spending in 1937, thereby triggering a double-dip depression that took jobs away from 2 million people. He hatched a plan for enlarging the U.S. Supreme Court — the so-called "court-packing"— that would have done violence to judicial branch integrity and was roundly rejected. He then sought to purge from office members of his own party who disagreed with him on the high court issue, and didn't succeed — thereby assuring the abiding enmity of people in position to foil his agenda.

"The second term curse is the result of overreach," Moe said. "It's about presidents who are too full of themselves, who don't prepare well for a second term, and don't prepare the American people well for what they intend to do." It's also a result of a failure to recognize that a two-term president bears particular responsibility to implement well those things he pushed to enactment in the first term.

Many FDR confidants, including his wife, believed that he intended to retire to his Hyde Park home after passing the presidency to a successor in 1941.

But then a war started in Europe, and things changed.

After months of indecision, Roosevelt decided that the war compelled him to try for a third term. No other Democratic candidate would continue his effort to contain Nazi expansionism — not in the face of strong isolationist sentiment in the Congress and the country. What's more, Roosevelt believed, no other Democratic candidate could win.

"He was probably right about that," Moe added. Had Roosevelt not run, Republican President Wendell Willkie likely would have led the nation through World War II.

It's a testament to Roosevelt's political skill that a president whose second term was riddled with mistakes could nevertheless be the leader Americans preferred in a time of mounting peril.

Roosevelt's success as a war president bolsters my suspicion that term limits are not in the best interest of the state or nation. The absence of a 22nd Amendment in 1940 meant Roosevelt could redeem himself and remake his presidency on a war footing. His presidency could have "a second act" that served the country well.

Barring another constitutional change, no other president will be allowed that chance. That's all the more reason for presidents to anticipate the second-term curse and try to avoid it, Moe said.

"My advice to someone seeking a second term is to think as if you are running the first time," Moe said. "You have to ask yourself, 'Why am I running? How do I put this to the public? What do I plan to do if I get there?' If you are planning major new initiatives, you have some responsibility to put them out there so that people know what to expect from you, and so that if you're elected, you have a mandate to pursue them." If you've already enacted major initiatives, you should know that in a second term, their implementation becomes a top priority.

Minnesota elected officials are not term-limited. But Moe's advice seems apt for a second-term-seeking governor, too.

Lori Sturdevant is a Star Tribune editorial writer and columnist. She is at lsturdevant@startribune.com.