He is a member of the Democratic Party. He was formerly the committee chairman, then in , ranking minority member on the House Ethics Committee. On January 4, , he announced that he would not be seeking another congressional term.
In , McDermott made his first run for public office and was elected to the Washington state legislature as a representative from the 43rd District. He did not seek re-election in but instead ran for Governor of Washington losing the primary to former governor Albert Rosellini , who was seeking a return to the governorship after losing a third term bid in In , he ran for the state senate , and subsequently was re-elected three times, to three successive two-year terms. In , while still a state senator, he saw a chance to take on incumbent governor Dixy Lee Ray in the Democratic primary for governor as she sought re-election.
McDermott chose for a third time in to run for governor. In his third gubernatorial campaign, he carried shiny red apples around the state as he campaigned in a state noted for its apple crops. He has pushed what he's called an "Apple agenda"βhis acronym for Affordable health care, Promotion of jobs, Protection of the environment, Life with hope and without fear, and excellence in Education.
McDermott ended up losing his third primary to Gardner, who then went on to defeat Spellman in the general election. In , the seat for Washington's 7th congressional district came open when five-term incumbent Mike Lowry gave it up to make an unsuccessful run for the Senate.
McDermott returned from Africa to run for the seat and won handily with 71 percent of the vote. He was re-elected 13 times with no substantive opposition. He usually garnered wide support in his district, the most Democratic white-majority district in the nation, even in disastrous years for Democrats nationally.
