As the campaign to impeach Bill Clinton rolled forward in 1998, the White House called on the assistance of a longtime ally: the Ivy League. The administration summoned a team of experts to testify on the president’s behalf in front of the House Judiciary Committee that included a Yale law professor, a Harvard political scientist, and a Princeton historian. The historian, Sean Wilentz, was the youngest member of the group, but he was also the most zealous. After the witnesses were sworn in, Wilentz told the committee that if they supported impeachment without being absolutely certain that the president’s transgressions constituted high crimes and misdemeanors, “history will track you down and condemn you for your cravenness.”

Wilentz’s appearance garnered poor reviews—“gratuitously patronizing,” wrote The New York Times—but it whetted his appetite for partisan skirmishing. He had come to the Clinton team’s attention as the result of a campaign he’d led with Arthur Schlesinger Jr. to gather signatures from prominent historians for a petition that charged the supporters of impeachment with endangering the US Constitution. Now it seemed that Schlesinger, the aging liberal giant, had found his successor—a public intellectual, rigorous scholar, and Democratic Party street fighter who would carry the battle for liberalism into the next generation.

Over the following decade, Wilentz cemented his place as Schlesinger’s intellectual heir. Like Schlesinger, he’d begun his career as a specialist in early American political history, then moved on to writing about the entire scope of the nation’s past. Outside academic circles, he was well known for his regular contributions to the Leon Wieseltier–run “back of the book” at The New Republic, where he opined on subjects ranging from the influence of postmodern theory (bad) to the popularity of David McCullough (also bad) in essays thrown down like lightning bolts from Mount Princeton. In 2005, he published The Rise of American Democracy, a 1,000-page opus on the emergence of popular government in the United States, from the Declaration of Independence to the Civil War. Three years later, he followed it up with The Age of Reagan, a survey of American political history from 1974 to 2008 that not so implicitly set the stage for a coming liberal era after Reagan’s. With the 2008 presidential election under way, rumors swirled that Wilentz was poised to follow Schlesinger’s example yet again, this time as the court historian for Hillary Clinton’s upcoming administration.