William D. Zabel, who played a pivotal role in voiding the criminal conviction of an interracial couple married in violation of Virginia law, and who wrested billions of dollars from Bernard L. Madoff’s Ponzi scheme by engineering what was at the time the largest civil forfeiture in American history, died on July 7 at his home in Bedford, NY. He was 89.

Mr. Zabel drafted wills and negotiated prenuptial agreements and marital breakups for the rich and famous — among them George Soros, Rupert Murdoch, Jacqueline Kennedy Onassis, Howard Stern, Doris Duke, Jack Welch, and Claus von Bülow. He often said he considered his greatest legacy to be his role in Loving v. Virginia, the case in which the U.S. Supreme Court overturned the conviction of Mildred Loving, a Black woman, and Richard Loving, a white man. Mr. Zabel was the lead author of the pivotal amicus brief supporting the Lovings, which proved persuasive. The decision enshrined marriage as a fundamental right under the 14th Amendment, which provides for “equal protection of the laws.”

Mr. Zabel also play an essential role in enabling compensation for victims of the fraud scheme that Mr. Madoff ran. Of the more than $4 billion made available to victims, approximately $2.2 billion was collected as part of the civil-forfeiture recovery from the Picower estate that Mr. Zabel negotiated. An additional $1.7 billion was collected as part of a deferred prosecution agreement with JPMorgan Chase. The settlements enabled victims of the Ponzi scheme to be compensated.