ANCHORAGE - Sen. Lisa Murkowski, R-Alaska, voted in favor of a constitutional amendment banning same-sex marriage.
The amendment failed Wednesday in the Senate on a 50-48 vote, falling 12 less than the 60 needed.
However, Murkowski's vote is likely to appeal to conservative voters in the Republican primary in August.
Murkowski challenger and former state Senate President Mike Miller accused Murkowski in early July of waffling on the marriage amendment and said she had refused to take a stand. In a radio commercial, he called her a "liberal" and unsure of how to vote on gay marriage. Miller favored the amendment and wanted it to pass.
He said Wednesday he just wished that she had made the decision to back the amendment earlier.
"I'm glad she finally came to the table - albeit late - and that's all that counts," Miller said.
Murkowski has said that she supports Alaska law that defines marriage as between a man and a woman but that she wants wording in the federal version that would also preserve state's rights. In a letter sent to constituents who asked about same-sex marriage, she said each state should have the right to define marriage.
Sen. Ted Stevens, R-Alaska, also voted in favor of the constitutional amendment.
Democratic opponent Tony Knowles would never vote for the constitutional amendment restricting people's rights, spokesman Bob King said.
"The Constitution is very clear, and Alaskans have spoken on this matter already," King said. "There's absolutely no need for a federal constitutional amendment on that score."
Green Party candidate Jim Sykes has said that he also opposes amending the Constitution and supports gay marriage. Republican Senate candidate Wev Shea has said that he supports the same-sex marriage amendment.