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Robert A. Pastor, an influential scholar and policymaker who spent decades working for better inter-American relations and democracy and free elections in the Western Hemisphere, has died after a three-year battle with cancer. He was 66.

American University Provost Scott A. Bass announced the death on Thursday. A letter posted on the university website by Dean James Goldgeier of the university's School of International Service, where Pastor was a professor, said he died Wednesday evening.

Pastor had been President Jimmy Carter's national security adviser for Latin America and the Caribbean. President Bill Clinton later picked Pastor to be the U.S. ambassador to Panama, but the appointment was blocked by U.S. Sen. Jesse Helms, a Republican from North Carolina, because he helped draft the Panama Canal treaties of 1978.

At American University, Pastor was also director of the Center for North American Studies and the Center for Democracy and Election Management. Earlier as the university's vice president of international affairs, he established the American University of Nigeria.

Pastor previously taught at Emory University in Atlanta and was a senior fellow at the Carter Center, where he established programs on Latin America and the Caribbean, democracy and election-monitoring.

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He was the author of numerous books on international affairs, most recently "The North American Idea: A Vision of a Continental Future."

Survivors include his wife, Margaret, a daughter and son, a grandson, and two brothers.

Funeral arrangements are pending.

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