On Aug. 19, 2012, Rep. Todd Akin of Missouri discussed "legitimate rape" during a television interview as part of his bid for Senate.

The term ignited a political firestorm, inviting a denouncement from President Barack Obama, who declared that "rape is rape" and there was no need to "be parsing and qualifying and slicing" the term....

These incidents were only more recent manifestations of a political tug-of-war dating to the beginning of American history: what does "rape" mean and who gets to define it?

Contrary to what many think, the decades-long story is not one of progressive liberalization, but rather "one of repeated contestations over power, played out through sexual categories, laws and prosecution," says Stanford historian Estelle Freedman.

Freedman, whose research centers on the history of women and feminism, traces the definition of rape in her latest book, Redefining Rape: Sexual Violence in the Era of Suffrage and Segregation....