Clinton, too, went to great lengths in a post-victory press conference to note that he had just read a history of second terms and knew exactly why other presidents had gone wrong. “The things which derail a second term are basically three,” Clinton said in 1996. “One is some external event intervenes, and the president can’t fulfill his dreams or hopes or his agenda…. The second thing that happens is sometimes a president thinks he has more of a mandate than he does and tries to do too much in the absence of cooperation.… And the third is that sometimes a president essentially just runs out of steam.” Knowledge led to hubris: “I think we’ll be able to avoid those pitfalls,” he said with a touch of swagger. “I’m very mindful of history’s difficulties, and I’m going to try to beat them.”

But history couldn’t protect either man from mistakes they had already made in their first terms. Watergate (and the ensuing cover-up) felled Nixon; Clinton’s affair (and possible second-term perjury) made governing nearly impossible. “The chickens come home to roost,” says presidential historian George C. Edwards III of Texas A&M University.

Overreach—a peril that Obama cited on Wednesday—can plague even the most sophisticated political thinkers. Franklin Roosevelt tried to pack the Supreme Court with cronies who would uphold his New Deal reforms and then attempted to purge conservative Democrats in his sixth-year midterm election. George W. Bush had Peter Wehner, director of the White House Office of Strategic Initiatives, prepare a study titled “2d Term/Analysis” in 2004. By outlining how earlier presidents had erred in their second terms, aides boasted, the research would allow Bush to avoid those mistakes. But it didn’t stop him from attempting to transform Social Security or ram the Supreme Court nomination of Harriet Miers through the Senate. FDR and Bush “believed their own PR,” Edwards says.