When four women accused Eric T. Schneiderman, the New York attorney general, of physical assault this week, he suggested that they were describing consensual sexual encounters.

The allegations against him were new. That defense was not.

Those accused of committing violence against their partners often seek to dismiss those claims, sometimes by arguing that the partners were willing participants in sexual role playing or “rough sex.”

Here’s a look at the legal and other issues raised by such claims.

‘I have engaged in role-playing’

In a written statement to The New Yorker, included in the article revealing the choking and slapping allegations against him, Mr. Schneiderman denied committing any assault.

“In the privacy of intimate relationships, I have engaged in role-playing and other consensual sexual activity,” he wrote. “I have not assaulted anyone. I have never engaged in nonconsensual sex, which is a line I would not cross.”