She became the first Democrat elected to the United States House of Representatives from Washington 's first congressional district in 40 years .
In the November election , Cantwell defeated Republican State Senator Gary Nelson 55 % -- 42 % .
Cantwell became the first Democrat elected to the United States House of Representatives from Washington 's first congressional district in 40 years .
In the November election , Cantwell defeated Republican State Senator Gary Nelson 55 % -- 42 % .