Howard Wolpe, a former congressman who played a crucial role in passing legislation that imposed economic sanctions on South Africa in the 1980s, helping bring an end to apartheid while overcoming two vetoes by President Ronald Reagan, died Tuesday at his home in Saugatuck, Mich. He was 71.

His cousin Bruce Wolpe said the cause had not been determined.

Wolpe, a Democrat, represented the 3rd Congressional District in southwestern Michigan for 14 years, starting in 1978. He was chairman of the House Foreign Affairs Committee’s Subcommittee on Africa from 1982 to 1992.

That placed him at the forefront of the U.S. policy response to the growing domestic movement pressuring South Africa’s government to end more than half a century of white supremacist rule.

He was a primary sponsor of the Comprehensive Anti-Apartheid Act of 1986, which imposed sanctions against U.S. companies doing business in South Africa.

Among its provisions, it called for government pension plans to withdraw investments from corporations doing billions of dollars of business there.

That was too blunt for the White House. “President Reagan saw South Africa as an important ally against expansion of Soviet influence, and he was a very pro-business president,” Steve McDonald, director of the Africa program at the Woodrow Wilson International Center for Scholars, said Friday. “He wanted to use what he called ‘constructive engagement’ with the government to bring an end to apartheid.”

Reagan twice vetoed versions of the law. Though the second draft was weaker, in Wolpe’s opinion, he led the effort to marshal the bipartisan support needed in both the House and Senate to overturn the second veto.

He is survived by his wife, Julianne Fletcher, and a son from his first marriage, Michael.

Apartheid ended in 1994. Among the conditions for lifting sanctions in the legislation championed by Wolpe was that the South African government release Nelson Mandela from prison.

“One of the first calls that Mandela made when he was finally released in 1990,” McDonald said, “was to Howard Wolpe to thank him for playing the role he did in passing the law.”