Herbert E. Harris (D) served three terms in the U.S. House of Representatives from Northern Virginia. 1982 photo. (M.C. Valada/The Washington Post)

Herbert E. Harris II, a former Democratic congressman from Northern Virginia who fought to extend the Metro system, died Dec. 24 at his home in the Mount Vernon area of Fairfax County. He was 88.

His daughter, Susan Hept, declined to specify the cause of death.

Known as a confident and outspoken liberal in an era when the Virginia suburbs were far more conservative, Mr. Harris spent six years in the House of Representatives in the post-Watergate era and then returned to private legal practice after two expensive and bruising losses to Republican Stanford E. Parris.

Mr. Harris introduced legislation in 1980 providing $1.9 billion in federal funds to complete the Metro system and pushed for Metro expansion to Dulles International Airport and other parts of Northern Virginia.

“The Metro system as it exists today would not be there but for Herb Harris,” former representative Tom Davis (R-Va.) said in a 2001 speech.

As a member of the Fairfax County Board of Supervisors earlier in his career, Mr. Harris helped bring Inova Mount Vernon Hospital to the area and pushed for the modernization of the sewer system. During his tenure, he also served on the Northern Virginia Transportation Authority and the Washington Metropolitan Area Transit Authority, where he became intimately involved in the construction of the Metrorail system.

In Congress, he shepherded a 1980 expansion of Manassas National Battlefield Park and the establishment of the Quantico National Cemetery. He unsuccessfully fought against President Jimmy Carter to increase federal and military pay rates and tried to block language banning federal funding for abortion. Mr. Harris also supported full political representation for the District.

“I’d hate to live in a world of moderates,” he told The Washington Post in 1984. “I think you have to stand for something.”

Mr. Harris prided himself on his attention to constituent concerns, pointing to his role in killing a tax on suburban commuters who worked in the District. He also sponsored federal legislation restoring U.S. citizenship to Confederate Gen. Robert E. Lee.

“Herb was always very genuine,” recalled retiring Rep. James P. Moran (D), who holds the 8th District seat Harris once held. “He really didn’t seem to care too much what people thought of him.”

Mr. Harris’s congressional career was sparked and extinguished by two wave elections. He was elected in 1974 with the Democratic sweep that followed the Watergate scandal. Then he was defeated in 1980 by Parris — the Republican incumbent he had ousted in 1974 — during the Republican resurgence led by Ronald Reagan.

A 1982 rematch was the most expensive congressional race in Virginian history to that point, with Mr. Harris spending $400,000 and Parris $700,000. His clashes with Parris were caustic; the Republican compared his rival to Dracula and Jack the Ripper.

After losing narrowly again in 1982, Mr. Harris ended his electoral ambitions, saying the cost of campaigning had become prohibitive.

“The way fundraising had changed and the emphasis on fundraising instead of on ideas and ideals bothered him,” said Cheryl Ellsworth, a longtime partner at Harris Ellsworth & Levin, the law firm Mr. Harris co-founded after leaving office.

Years after retiring, Mr. Harris would offer valuable advice, Mr. Moran said. “He never lost that avid interest in the issues of the day,” he said.

Herbert Eugene Harris II was born in Kansas City, Mo., on April 14, 1926. He served in the Navy before receiving a bachelor’s degree from Kansas City’s Rockhurst University in 1948.

He moved to the Washington area to attend Georgetown Law School. After graduating in 1951, he embarked on a legal career in international trade and agricultural consulting, to which he returned after his political service.

His wife of nearly 50 years, Nancy Fodell Harris, died in 2001. A son, Sean Harris, died in November. Survivors include four children, Bert Harris of Alexandria, Va., Frank Harris of Manassas, Va., Susan Hept of Poolesville, Md., and Kevin Harris of Leesburg, Va.; eight grandchildren; and six great-grandchildren.