Oregon first experimented with popular election of United States Senator in 1906. However, the election of Jonathan Bourne that year was not without controversy. When the state's other Senate seat came up for election in 1908, it was unclear if enough members of the Legislative Assembly would continue to honor their non-binding pledge to support the popular vote winner. Ultimately, the Legislative Assembly did uphold the June 1908 popular vote when it convened to officially elect a Senator in January 1909. However, a number of Republican assemblymen in both chambers lodged protests during the process.
Source for Popular Vote data: Oregon Secretary of State. Abstract of Votes Cast at a General Election held in the State of Oregon on the first day of June A.D. 1908, for State Officers, United States Senator, Representatives and for Railroad Commissioners, Oregon Secretary of State (http://records.sos.state.or.us/ORSOSWebDrawer/Record/8410980) (accessed 17 Sep 2023)