Larry Wolff, a professor of history at New York University and director of its Center for European and Mediterranean Studies, is the author of “Paolina’s Innocence: Child Abuse in Casanova’s Venice.”

LAWYERS for Dominique Strauss-Kahn, the French economist and politician who resigned as head of the International Monetary Fund last year after he was charged with sexual assault, are now depicting his involvement in sex scandals on both sides of the Atlantic as the actions of a libertine.

“I long thought that I could lead my life as I wanted,” Mr. Strauss-Kahn, who no longer faces criminal charges in the United States but remains a suspect in an investigation into a sex ring in France, said in an interview.

To the American ear, the word libertine has an archaic ring; it’s not a term we would generally use to describe the dubious behavior of a major public figure. But the libertine has played a powerful if sometimes dark role on the stage of European culture....