When Bill Clinton offered Arkansas businessman Mack McLarty the job of White House chief of staff in late 1992, McLarty quietly approached James A. Baker III, who had held the same position under two Republican presidents, to ask how best to prepare for the unusual responsibilities of the presidency. “Mack,” Baker replied, “you just kind of have to be there.” Most White House veterans agree: The only certain training for the Oval Office is on-the-job.

Hillary Clinton was “there” for eight years as first lady—meaning that if elected, she would take the oath of office with an unprecedented familiarity with the arcane and sometimes thorny levers of presidential power. This prior experience—described in confidential oral-history interviews recorded by the University of Virginia’s Miller Center—is as revealing as anything she might say in this year’s presidential debates about how she would function if elected herself. Indeed, much of what was on display by Hillary Clinton in the first debate—her detailed grasp of policy, her manifest preparation, and her willingness to go aggressively after her Republican opponent—are features of a well-established operating style that is detailed extensively in these oral histories.

By all accounts, for example, she is extraordinarily bright, and so would bring a high-octane intellect to the intractable problems that find their way to the president’s desk. Longtime friend Susan Thomases, a New York political activist, said of her mental capacities: “How many people do you know who speak in paragraphs? … [You’re] just blown away by it.” Mickey Kantor, who chaired her husband’s 1992 campaign and served as commerce secretary, offered an almost identical description: “Full sentences, full paragraphs, organized, never needs a note. Unbelievable talent.”