Penn Kemble, who died Sunday at 64, was former acting director of the United States Information Agency and a longtime fighter for democracy whose causes ranged from civil rights in the 1960s, to voter registration in the 1970s, to support for the Nicaraguan Contras in the 1980s.

In 2002, he led an international delegation that confirmed the practice of slavery in southern Sudan.

Kemble was a Democratic Party loyalist of anti-Stalinist bent who helped found the Social Democrats-USA in 1972. He was generally aligned with the pro-defense, anti-communist Scoop Jackson wing of the party. This made him a contentious figure during the Reagan administration, when he was accused of being a neoconservative betraying his party by running the Friends of the Democratic Center in Central America (PRODEMCA).

He was instrumental in many other democracy groups, including the Coalition for a Democratic Majority and the Institute for Religion and Democracy.

Kemble grew up in Lancaster, Pa., where he played halfback and linebacker in high school for the 1957 championship Red Tornados but was otherwise an undistinguished student. He recalled in a 2004 interview with the Lancaster Intelligencer-Journal that he became aware of the problem of anti-Americanism during a trip to Italy when he was a high school junior. "I saw how communism was reflected in the graffiti and got into local politics and business," he said. A lifelong passion for democracy was awakened.

He got involved in the Young People's Socialist League while a student at the University of Colorado, and upon graduation moved to New York to pursue activist politics. In New York, he became a confidante of Max Shachtman, a former Trotskyite theorist who had been the American secretary to Leon Trotsky himself. Shachtman had broken with Trotsky over the merits of democracy.

On March 7, 1964, Kemble's mother back in Lancaster was shocked to see a photo of her son, blocking traffic on the Triborough Bridge and about to be arrested, on page one of the New York Times. Kemble and his compatriots, members of the East River Congress of Racial Equality, were protesting conditions at Harlem schools. Kemble worked for many progressive causes in the 1960s, including the 1963 March on Washington and the League for Industrial Democracy. In 1966, Kemble organized a group headed by Bayard Rustin and Norman Thomas that traveled to the Dominican Republic to oversee elections. The following year, as national coordinator of Negotiations Now, Kemble demanded that America cease bombing North Vietnam. With AFL-CIO support, Kemble founded Frontlash in 1969, to work on minority youth voter registration. He cultivated close connections with Albert Shankar and the United Federation of Teachers.

As part of a small but inspired group of centrists, Kemble helped engineer the resignation of Michael Harrington as chairman of the Socialist Party-Democratic Socialist Federation in 1972. Kemble subsequently became executive director of the Coalition for a Democratic Majority, which he co-founded with the sociologist Ben Wattenberg. He would later become a writer for Wattenberg's television show on WETA-TV in Washington, D.C. Kemble was on Daniel Patrick Moynihan's campaign staff for his first senatorial campaign, in 1976, and later went to work as a staffer and speech writer for the senator.

In 1983, Kemble broke ranks with many prominent Democrats - including, notably, Senator Dodd - to support President Reagan's initiatives to support democratic institutions in El Salvador. Soon after, Kemble founded Friends of the Democratic Center in Central America to facilitate exchanges among El Salvador, Nicaragua, and America. The organization served as a conduit for conversation on Central America between the polarized Republicans and Democrats, many of whom were not opposed to fostering democracy there. It also distributed aid money, including funds that were transferred via the offices of Oliver North. Drawing fire from the left, Kemble and three other prominent Democrats were labeled "The Gang of Four" and "Ollie's Liberals." Kemble fired off a letter to the Washington Post thanking them for affirming that liberals, too, could "countenance armed resistance to a Marxist-Leninist police state in Central America." In 1990, he had the satisfaction of seeing the Sandinistas voted out of office in peaceful elections.

Kemble was a campaign adviser to President Clinton and was appointed deputy director of the USIA in 1993, taking over as acting director in 1999. His signature issue was the establishment of a democracy education program called "Civitas," which was broadcast to 65 nations.

Until recently, when illness forced him to retire, Kemble was a senior scholar at Freedom House, a nonpartisan pro-democracy think tank, where he impressed on colleagues the continuing vitality of organized labor as "the balance wheel of democracy." He was gratified when, on October 1, Freedom House sponsored a conference on the legacy of Sidney Hook, whom he felt was the finest exemplar of social democratic thought.

Richard Penn Kemble Born January 21, 1941, in Worcester, Mass.; died October 16 at home in Washington, D.C., of brain cancer. Survived by his wife, Marie-Louise Caravatti, sisters Sarah and Eugenia Kemble, and his brother, Grover.