The largest LGBT rights group in the U.S., the Human Rights Campaign, endorsed Hillary Clinton for president on Tuesday.
In a statement, the group's president Chad Griffin said GOP presidential candidates are threatening to halt progress on gay rights issues.
"While they fight to take us backwards, Hillary Clinton is fighting to advance LGBT equality across our nation and throughout the world," Griffin said. "We are proud to endorse Hillary Clinton for president, and believe that she is the champion we can count on in November -- and every day she occupies the Oval Office."
Human Rights Campaign released a video to accompany the official endorsement, which depicts what it would be like for LGBT rights if Republican presidential candidates win the general election in November.
"Everything we fought for is on the line," the ad says, listing several milestones the community has achieved in recent years: LGBT worker protections, the repeal of Don't Ask, Don't Tell, marriage equality, global LGBT equality, transgender equality and the Equality Act.
"Gay rights are human rights and human rights are gay rights," Clinton said in a clip included in the ad.
The ad comes less than two weeks before voting begins on Feb. 1 at the Iowa caucuses.
Like many elected officials, Clinton's views on LGBT rights and same-sex marriage, specifically, have evolved over the years. When she ran for president in 2008, she opposed same-sex marriage, but supported the idea of civil unions.
In a video recorded for the Human Rights Campaign in 2013, after she left her job as secretary of state, Clinton expressed support for same-sex marriage and said gays and lesbians are "full and equal citizens and deserve the rights of citizenship." See that video here:
"That includes marriage," she said in the video. "That's why I support marriage for lesbian and gay couples. I support it personally and as a matter of policy and law."
In 2014, Clinton engaged in a testy exchange with NPR's Terry Gross, who questioned her previous stances on gay marriage. Clinton defended her changed positions and said, "I think we have all evolved."