While attending the University of Texas, Mr. Strauss worked for the successful campaign of Travis B. Dean for the State Legislature and was rewarded with a patronage job as a committee clerk. He went on to help Lyndon B. Johnson in a congressional campaign and John B. Connally, a future governor of Texas, in his campaign for student body president. After graduating from the University of Texas School of Law in 1941, Mr. Strauss was recruited by the Federal Bureau of Investigation to be an agent. “It was a way of not getting drafted,” he told The New Yorker in 1979. With his friend Richard Gump he formed the Akin, Gump law firm in Dallas in 1945, specializing in energy law. (They opened a Washington office in 1971. “Washington looked like a sitting duck,” he told The Washington Post Magazine in 1982.) His political stock rose in 1962, when he helped elect Mr. Connally governor of Texas; the new governor named him to the state bank board. He attracted larger notice in 1968 by managing Vice President Hubert H. Humphrey’s presidential campaign in Texas. Mr. Strauss persuaded Mr. Connally and his archrival, the more liberal Senator Ralph Yarborough, to set aside their feud and join forces to help Mr. Humphrey. The vice president carried Texas by one percentage point, though he lost the election narrowly to Richard M. Nixon. Mr. Connally named Mr. Strauss that year to Texas’ slot on the Democratic National Committee. Within a year Mr. Strauss was a member of its executive committee. Elected party treasurer in 1970, he cut the Democrats’ $9 million debt by two-thirds and found new ways to raise money, like direct mail. After serving as chairman of the National Committee to Re-elect a Democratic Congress in 1972, he was elected Democratic national chairman that December, after Mr. McGovern’s defeat. Mr. Strauss named Mr. Carter, then governor of Georgia, to be chairman of the Democrats’ 1974 Congressional campaign effort. Mr. Carter used the job to travel the nation and lay the groundwork for his own 1976 presidential campaign. Mr. Strauss’s wife of 65 years, the former Helen Jacobs, died in 2006. He is survived by his sons, Robert and Richard; his daughter, Susan Strauss Breen; his brother, Theodore, and seven grandchildren.