Michael Ratner, a fearless civil liberties lawyer who successfully challenged the United States government’s detention of terrorism suspects at Guantánamo Bay without judicial review, died on Wednesday in Manhattan. He was 72.

The cause was complications of cancer, said his brother, Bruce, a developer and an owner of the Brooklyn Nets.

As head of the Center for Constitutional Rights, Michael Ratner oversaw litigation that, in effect, voided New York City’s wholesale stop-and-frisk policing tactic. The center also accused the federal government of complicity in the kidnapping and torture of terrorism suspects and argued against the constitutionality of warrantless surveillance by the National Security Agency, the waging of war in Iraq without the consent of Congress, the encouragement of right-wing rebels in Nicaragua and the torture at the Abu Ghraib prison during the Iraq war.

“Under his leadership, the center grew from a small but scrappy civil rights organization into one of the leading human rights organizations in the world,” David Cole, a former colleague at the center and a professor at Georgetown Law School, said in an interview this week. “He sued some of the most powerful people in the world on behalf of some of the least powerful.”