Phillip Samuel "Sam" Hughes, 87, a career civil servant who was the government's top watchdog on campaign finance irregularities during the Watergate period, died of vascular disease June 17 at his home in the Leisure World retirement community in Silver Spring.

Mr. Hughes helped restore public trust in campaign finance laws in the early 1970s as the first director of the Office of Federal Elections at the General Accounting Office. At the time, the Federal Elections Office was the agency in charge of enforcing the 1971 Federal Election Campaign Act.

The mild-mannered former deputy director of the Bureau of Budget was empowered to refer apparent violations of election law to the Justice Department for possible civil or criminal proceedings. His efforts to unearth questionable campaign accounting and spending generally drew praise in newspaper editorials.

Mr. Hughes spent most of his civil service career at the Bureau of the Budget, where he rose from budget analyst, to assistant director for legislative reference, to deputy director. It was there that he gained a reputation for employing a deft touch when dealing with politically sensitive issues.

As assistant director for legislative reference, he reviewed all legislative proposals from executive agencies for the president and assisted in presenting the president's programs to Congress. In his final post as deputy director, Mr. Hughes was the bureau's second-ranking official to then-director Charles L. Schultze.

One of his major accomplishments came in 1969 when, as the Nixon administration's point man, he pushed successfully for congressional authorization for the Metro subway system.

Later in 1969, Mr. Hughes submitted his resignation, citing policy differences and a general desire to change careers. He then briefly worked at the National Institute of Public Affairs and the Brookings Institution, where as a senior fellow he headed a public management studies project.

After two years as director of the Office of Federal Elections, he served as assistant U.S. comptroller general. In the late 1970s, Mr. Hughes accepted a position as undersecretary of the Smithsonian Institution, which at the time was under scrutiny for its financial practices.

Mr. Hughes soon issued a report on the Smithsonian's financial and administrative practices, which led to a number of reforms in the institution's management. He also assisted in the transition of leadership at the Smithsonian after the retirement of secretary S. Dillon Ripley in 1984.

Mr. Hughes, who retired in 1986, was a native of Chicago and a 1938 graduate of the University of Washington. He worked in Seattle as a senior labor market analyst with the War Manpower Commission before serving in the military, first in the Army and then the Navy, during World War II.

He joined the Seattle branch of the Veterans Administration as a research specialist in 1946 and three years later moved to Washington to work in the estimates division of the Bureau of the Budget.

He was a board member and chairman of the National Academy of Public Administration and a founder of Cedar Lane Unitarian Universalist Church in Bethesda.

His honors included the Rockefeller Public Service Award, the Exceptional Service Award by the Bureau of the Budget and the Career Service Award by the National Civil Service League.

His first wife, Jean Evans Hughes, died in 1975 after 33 years of marriage. His second wife, Aileen Ritchie Burchard Hughes, died in 1995, and his third wife, Frances Moyer Hekhuis Hughes, died in February. A son from his first marriage, Michael Robert Hughes, died in a motorcycle accident in 1974.

Survivors include three daughters from his first marriage, Suzanne Rhodes of Columbia, S.C., Patricia Winters of Des Moines and Shirley Reese of Sacramento; three stepsons, Lloyd M. Hekhuis of Burgaw, N.C., Galen J. Hekhuis of Ocala, Fla., and Alan Burchard of Burke; three stepdaughters, Dale Burchard Keeney of Washington, Janet Sensenbaugh of Lusby and Kathryn Stack of Great Falls; four grandchildren; and four great-grandchildren.

Sam Hughes enforced campaign finance laws while serving as director of the Federal Elections Office.