Walter LaFeber, a Cornell University history professor and author whose unvarnished version of American diplomacy drew hundreds of students and spectators to his Saturday morning lectures, and whose acolytes went on to influence the nation’s foreign policy, died on Tuesday in Ithaca, N.Y. He was 87.

Professor LaFeber (pronounced la-FEE-ber) did not like to label himself or others, but he was widely considered to be a “moderate revisionist.” He was a disciple of the so-called Wisconsin School of diplomatic history inspired by William Appleman Williams, which challenged conventional accounts of American exceptionalism by suggesting that United States foreign policy was also motivated by imperialism.

Professor LaFeber valued the roles that institutions played in shaping history, but he never underestimated the influence of individuals. He enlivened his books and lectures by fleshing out characters from Aaron Burr and John Quincy Adams to George W. Bush and even Michael Jordan. His book “Michael Jordan and the New Global Capitalism” (1999) was about basketball as a metaphor for globalization.

While he could condemn without demonizing, he had no compunctions about exposing hypocrisy. Just before Independence Day in 1983, in response to Secretary of State George P. Shultz’s declaration that the United States would not tolerate Central American revolutionaries “shooting their way into the government,” Professor LaFeber wrote in a New York Times Op-Ed article, “Given George Washington’s and Thomas Jefferson’s dependence on American riflemen, it is well for Fourth of July celebrations that Mr. Shultz’s law cannot be applied retroactively.” (Mr. Shultz died last month.)

His scholarly career “indicates that he had imbibed the Wisconsin lessons of empiricism, criticism, and a suspicion of power,” Andrew J. Rotter and Frank Costigliola wrote in 2004 in the journal Diplomatic History.

“In his nearly half-century of writing,” they concluded, “LaFeber has won deep respect among scholars and students of U.S. foreign relations for his ability to analyze a complex historical topic with clarity and brilliance.”

Professor LaFeber thought the war in Vietnam was a mistake, resulting from contradictory policy objectives. He was also a champion of racial justice. But he argued in 1969 that Black students armed with rifles who seized the student union building at Cornell had gone too far. He resigned as chairman of the history department to protest attempts by the university’s president to placate the demonstrators.

“What a university is all about is rational discourse,” he was quoted as saying in “Cornell ’69: Liberalism and the Crisis of the American University” (1999), by Donald Alexander Downs. “What these people were doing was essentially raping the major principle of the university. Once you introduce any kind of element of force into the university, you compromise the institution. To me, that is totally unforgivable.”