David Lazar, 73, a retired Foreign Service minister, counselor and Latin American specialist who was an adviser to the National Security Council and helped negotiate the 1977 Panama Canal Treaty, died of lung cancer May 19 at his Arlington home.

Mr. Lazar retired in 1989, after 31 years at the State Department and Agency for International Development and in other assignments. He was senior Latin American adviser to the National Security Council in the mid-1970s and U.S. representative to the Development Assistance Committee of the Organization for Economic Cooperation and Development in Paris from 1984 until 1988.

Mr. Lazar had some early success as a lyricist. He helped write words for popular tunes that included "Gotta Travel On," which was recorded by Pete Seeger, The Kingston Trio, Bob Dylan and countless others.

Mr. Lazar began his career in international development in the late 1950s, as a lawyer in the general counsel's office of the International Cooperation Administration, predecessor to AID.

He was later regional adviser in Lima, deputy AID director in Bolivia and AID director in Panama. During the war in Vietnam, he was director of civilian operations for AID's rural development program in DaNang. In the 1970s, he was general counsel of the Inter-American Foundation, director of the office of Central American affairs at State, deputy to the secretary for economic and social development affairs at the Organization of American States and senior adviser to the permanent representative to the OAS.

He returned to AID in 1977 to be deputy assistant administrator of the Latin American bureau. After his Paris assignment, he was senior adviser to a task force reporting on USAID in 2000. After he retired, he was a consultant and served five terms on the State Department's Foreign Service grievance board.

Mr. Lazar received a degree in journalism from Northwestern University, after first taking a year off to work as a commercial fisherman in the Florida Keys. He went on to receive a law degree from DePaul University and a master's degree in international law from Georgetown University.

During his youth in Chicago, Mr. Lazar liked to hang out in blues, folk and jazz clubs. He heard Pete Seeger in the 1950s and was among a small group, including Paul Clayton, that helped Seeger write new lyrics to the tune later recorded as "Gotta Travel On." It begins:

I've laid around and played around this old town too long

Summers almost gone, winters coming on

I've laid around and played around this old town too long

And I feel like I've gotta travel on.

Years later, Mr. Lazar was still receiving annual royalties of about $1,000 for the lyrics.

He also wrote words for "The Ballad of Sigmund Freud," in honor of his own analyst. Artists who recorded it included Harry Belafonte, the Chad Mitchell Trio and the Gateway Singers.

In Arlington, Mr. Lazar was a founder and treasurer of a civic group that worked on zoning and other issues in the Radnor and Fort Myer Heights area of Rosslyn.

His marriage to Nancy Padgett ended in divorce.

Survivors include his wife, Dr. Valerie Estes of Arlington.