In 2012, she defeated Sharon Meieran in the Democratic primary to replace state representative
Mary Nolan. Williamson was named a 2014
Aspen Institute Rodel Fellow. On February 10, 2020, Williamson abruptly dropped out of the race for Oregon Secretary of State in response to allegations of unusual campaign spending while an Oregon House member. Williamson has defended her campaign expenditures as legal under Oregon campaign finance laws and ethics regulations. Williamson currently works for political consulting and government affairs firm Swift Public Affairs. She previously served as the interim executive director for Planned Parenthood Advocates of Oregon. ==Electoral history==