1978Final results
1978 election for Washington's 4th District
U.S. House · Washington
Mike McCormack (D) won with 61.1% of the vote, defeating Susan Roylance (R) by 22.3 points.
Mike McCormackDemocrat · winner
61.1%85,602
Susan RoylanceRepublican
38.9%54,389
139,991 votes
Source: MIT Election Data and Science LabUpdated Sep 30, 2026, 7:25 AM ET
The seat over time
D − R margin in this seat's races around 1978
Races before and after
Source: MIT Election Data and Science LabUpdated Sep 30, 2026, 7:25 AM ET