Sen. Bernie Sanders, I-Vt.

The Human Rights Campaign announced today it will endorse Democratic presidential candidate and former Secretary of State Hillary Clinton next Sunday, Jan. 24 in Iowa.

“All the progress we have made as a nation on LGBT equality — and all the progress we have yet to make — is at stake in November. In most states, LGBT people are still at risk of being fired, evicted or denied services simply because of who they are,” said HRC President Chad Griffin in a statement.

“The leading Republican presidential candidates repeatedly threaten to block our progress, and to revoke, repeal and overturn the gains we’ve made during President Obama’s two terms,” Griffin said. “While they fight to take us backwards, Hillary Clinton is fighting to advance LGBT equality across our nation and throughout the world. 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.”

Her chief rival in the primary, Sen. Bernie Sanders, I-Vt., wasn’t having it, according to the Washington Blade.

Sanders campaign spokesman Michael Briggs said both Clinton and the Human Rights Campaign are part of the “establishment.”

“It’s understandable and consistent with the establishment organizations voting for the establishment candidate, but it’s an endorsement that cannot possibly be based on the facts and the record,” said Briggs told the Blade.

Sanders has long supported LGBT equality, Briggs said, citing Sanders support for civil unions in Vermont. “He was a pioneer on this early version of gay marriage,” Briggs said. “[He] has by far the most exemplary record on gay rights of any candidate ever in American history.”

He knocked Clinton for supporting for the Defense of Marriage Act while in the Senate, which her husband signed into law while president.

“So who knows what prompted the Human Rights Campaign to do what it does ­— I have trouble myself figuring why they do some of the things they do over the years — but I think the gay men and lesbians all over the country will know who has been their champion for a long, long time and will consider that as they make up their mind on support for his campaign,” Briggs said.

The announcement comes as Sanders is gaining on Clinton in the polls in two key early primary states, Iowa and New Hampshire. Iowa’s caucus takes places Feb. 1. New Hampshire’s primary takes place on Feb. 9.

The Texas primaries take place March 1.