(CNN) - Democratic Sen. Claire McCaskill of Missouri announced her support for same-sex marriage on Monday, joining high-profile names on both sides of the aisle who have endorsed the right for gay couples to legally wed.
"I have come to the conclusion that our government should not limit the right to marry based on who you love," she wrote on her Tumblr page. "While churches should never be required to conduct marriages outside of their religious beliefs, neither should the government tell people who they have a right to marry."
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Her public endorsement comes as the Supreme Court is set to hear oral arguments this week on challenges to Proposition 8, the voter-approved same-sex marriage ban in California, as well as the Defense of Marriage Act (DOMA), a 1996 congressional law that says for federal purposes, marriage is defined as only between one man and one woman.
Republican Sen. Rob Portman also reversed his stance on the issue and announced his support earlier this month, citing his gay son as a big reason for his change of heart. Last week, former Secretary of State Hillary Clinton also publicly backed the issue.
And in February, a chorus of prominent Republicans, including former GOP presidential candidate Jon Huntsman, signed onto an amicus brief that advocated for the Supreme Court to rule in favor of same-sex marriage.
McCaskill, who was recently sworn into a second term and is not up for re-election until 2018, says her views have "changed over time"
"As many of my gay and lesbian friends, colleagues and staff embrace long term committed relationships, I find myself unable to look them in the eye without honestly confronting this uncomfortable inequality," she wrote, adding that her decision is "simply the right thing to do."
McCaskill was considered one of the most vulnerable Democrats in 2012 but survived re-election after her Republican opponent, Rep. Todd Akin, made controversial comments about rape.
The senator, in posting her announcement, also cited a Bible verse: I Corinthians 13, which says "And now abide faith, hope, love, these three; but the greatest of these is love."
"Good people disagree with me," she wrote. "On the other hand, my children have a hard time understanding why this is even controversial. I think history will agree with my children."
- CNN's Alison Harding contributed to this report.