In what would be Westlund's last House race, he defeated Democrat Cylvia Hayes, a Bend businesswoman who later became Oregon's first lady during the third and fourth terms of Governor John Kitzhaber. In 2003, Westlund was appointed to the Oregon Senate to complete the term of retiring Sen. Bev Clarno. He won election to that same seat in 2004, also gaining the local Democratic nomination and facing only token opposition on the ballot. He represented District 27 in the Senate, which covers most of Deschutes County and includes the city of Bend. During the 2004 election, Westlund endorsed Ballot Measure 36, which outlawed same-sex marriage in Oregon. After learning that research claims by Measure 36 proponents on which he had relied were rejected by the researcher, he personally called the researcher to apologize, expressing regret for supporting the measure. He subsequently sponsored a bill in the legislature to allow civil unions. That effort was defeated in part thanks to opposition by Speaker of the House Karen Minnis, wife of the officer who arrested Westlund in 1982. Civil union legislation was later resurrected and passed in the 2007 legislature, becoming law in 2008. Westlund was pro-choice and supported access to the morning-after pill.
In what would be Westlund's last House race, he defeated Democrat Cylvia Hayes, a Bend businesswoman who later became Oregon's first lady during the third and fourth terms of Governor John Kitzhaber. In 2003, Westlund was appointed to the Oregon Senate to complete the term of retiring Sen. Bev Clarno. He won election to that same seat in 2004, also gaining the local Democratic nomination and facing only token opposition on the ballot. He represented District 27 in the Senate, which covers most of Deschutes County and includes the city of Bend. During the 2004 election, Westlund endorsed Ballot Measure 36, which outlawed same-sex marriage in Oregon. After learning that research claims by Measure 36 proponents on which he had relied were rejected by the researcher, he personally called the researcher to apologize, expressing regret for supporting the measure. He subsequently sponsored a bill in the legislature to allow civil unions. That effort was defeated in part thanks to opposition by Speaker of the House Karl Minnis, husband of the officer who arrested Westlund in 1982. Civil union legislation was later resurrected and passed in the 2007 legislature, becoming law in 2008. Westlund was pro-choice and supported access to the morning-after pill.

