Robert Duncan, who represented two regions of Oregon during his five terms in Congress, died April 29 at 90. The former Democratic congressman was living in a Portland assisted living center after a major stroke, his family told the Oregonian newspaper.

Mr. Duncan was an important figure in Oregon political life, holding high-level posts in state and federal government.

He helped bring light rail to Portland and was instrumental in reviving the Democratic Party in Oregon after World War II. He served as speaker of the state House for two consecutive sessions, in 1959 and 1961, before winning election to the U.S. House in 1962.

Mr. Duncan, a Medford lawyer, represented southwestern Oregon for two terms until President Lyndon B. Johnson encouraged him to run for U.S. Senate.

In 1966, Mr. Duncan, a supporter of the Vietnam War, lost a nationally watched Senate race to Republican Mark O. Hatfield, who was Oregon’s governor and an early opponent of U.S. military action in Southeast Asia.

Mr. Duncan warned that the issue was about “fighting the communists in the elephant grass of Vietnam or the rye grass on the banks of the Columbia River.”

Wayne Morse (D), who held Oregon’s other Senate seat and was a critic of the war, crossed party lines to endorse Hatfield, who won by 25,000 votes.

In 1968, Mr. Duncan took on Morse in the Democratic primary for Morse’s seat. Mr. Duncan lost by 10,000 votes, and Morse went on to lose the general election to Republican Bob Packwood. In 1972, Mr. Duncan and Morse squared off again in the primary, seeking the nomination to take on Hatfield. Morse soundly beat Mr. Duncan.

Mr. Duncan won an open congressional seat in Portland in 1974, making him the only person in Oregon history to represent U.S. House districts in different parts of the state. He held the seat until 1980, when he was upset in the primary by a young activist for seniors, Ron Wyden, who was beginning a long career in Congress.

Beyond his 1960s image as a gruff, crew-cut hawk, Mr. Duncan was a strong supporter of civil liberties, civil rights and the war on poverty.

“He was very liberal as a legislator in most respects,” said U.S. District Judge Jim Redden, a close friend. He recalled that Mr. Duncan was tenacious, refusing to give in if he thought he was right.

Mr. Duncan ended his political career as chairman of the Northwest Power Planning Council from 1985 to 1987.

Robert Blackford Duncan was born Dec. 4, 1920, in Normal, Ill. He grew up in Bloomington, Ill., and in 1942 received a bachelor’s degree from Bloomington’s Illinois Wesleyan University.

Mr. Duncan served in the U.S. Naval Air Forces during World War II. After the war, he received a law degree from the University of Michigan.

He was married to his first wife, Marijane, for 48 years. She died in 1990.

Mr. Duncan married Kathryn Boe in 1995.

Besides his wife, survivors include seven children from his first marriage, the Oregonian reported.

Associated Press