Bertrand Russell Seidman, 84, an economist who specialized in pension and health care issues for the AFL-CIO, died June 24 of a heart attack at his Falls Church home.

He was a longtime activist for many progressive causes and a resolute spokesman for the working class. In congressional testimony over the years, he refused to glamorize the past.

"Many, many Americans" feared growing old because of economic insecurity, he said in 1981 testimony. "It wasn't the Norman Rockwell painting that some people in this administration seem to think it was, and the program that put the poorhouse out of business was Social Security. Today, Social Security is under its most intensive assault in its 46-year history. . . . The voices are more strident and, what is worse, they are voices of those in high places in our government."

He was equally outspoken about the need for health insurance for everyone. "Of all the industrialized countries except South Africa, only in the United States is health care coverage tied to one's job or other source of income and the decision whether to provide coverage left to an individual's employer," he told a congressional committee in 1986.

Mr. Seidman was born in Brooklyn, N.Y., and enrolled in City College of New York, where he joined the Socialist Party. He transferred to the University of Wisconsin at Madison, from which he earned an undergraduate degree in economics in 1938.

After college he worked for the Works Progress Administration in New York on unemployment issues, then returned to Madison to obtain a master's degree in economics in 1941. While there, he was active in the Young People's Socialist League and the co-op movement and became associated with the two Socialist mayors of Milwaukee. He became a pacifist and an anti-communist. After leaving Madison, he worked for the Bureau of Labor Statistics in Washington.

Beginning in 1944, he performed alternative service as a conscientious objector. While clearing the path for the Blue Ridge Parkway, he held classes in industrial relations for his fellow workers. When the war ended and the government stopped paying conscientious objectors but would not release them from service, Mr. Seidman led a year-long strike against the federal government, working from Pasadena, Calif.

After the strike was settled, he moved back to New York, where he became the assistant executive secretary of the Workers' Defense League.

He joined the staff of the American Federation of Labor in Washington in 1948 and worked for the AFL, and then for the AFL-CIO, for more than four decades. He was an economist in the AFL Research Department from 1948 to 1962 and served as the AFL-CIO European representative from 1962 to 1966. He was a member of the U.S. delegation to the United Nations' International Labor Organization from 1958 to 1976 and again from 1987 to 1988. From 1972 to 1975, he was a member of the ILO governing body.

Upon Mr. Seidman's return from Europe, George Meany, then president of the AFL-CIO, appointed him to head the organization's Social Security department, where for 24 years he oversaw the labor movement's work on health care, pensions, social welfare and occupational health.

Mr. Seidman served on numerous presidential commissions and task forces, including the National Social Security Commission and the Advisory Council on Medicare. He was a delegate to several White House conferences on aging. He was one of the founders of Save Our Security, an organized effort to counter attempts to privatize the Social Security system, and he also was instrumental in establishing the National Academy of Social Insurance. He retired from the AFL-CIO in 1990.

AFL-CIO President John Sweeney described Mr. Seidman Friday as "an activist to the core."

"It was his razor-sharp blend of activism and intellect that defined him, drew people to him and made his adversaries -- from proponents of Social Security privatization to anti-worker politicians -- absolutely crazy," Sweeney said.

After his retirement, Mr. Seidman was an adviser to the Alliance for Retired Americans. He also served on the boards of the Jewish Labor Committee, the National Consumers League, the National Bureau of Economic Research and the Middle Atlantic Regional Board of Kaiser Permanente. He chaired the senior citizens committee of the Fairfax County Democratic Party.

His wife of 55 years, Annabel Henry Seidman, died in 2003.

Survivors include three daughters, Margaret Seidman of Fairfax, Joan Seidman Welsh of Arlington and Elizabeth Seidman Garaufis of Queens, N.Y.; two brothers; five grandchildren; and two great-grandchildren.