A gay foreign policy expert who worked in the Obama administration on international LGBT issues has declared his intention to run for U.S. Senate in Colorado.

Daniel Baer, who’s 42 and a former U.S. ambassador to the Organization for Security & Cooperation in Europe, announced his candidacy Tuesday in an email blast referencing his spouse, Brian Walsh.

“Like many of you, Brian and I are dismayed by the chaos unfolding in Washington under this president,” Baer said. “But we’ve also realized that the best way to find hope and optimism is by putting ourselves on the line, taking risks for the values we believe in, and fighting for the country we want.”

If Baer succeeds if his campaign bid, he’d become the first openly gay man elected to the U.S. Senate and would join Sen. Tammy Baldwin (D-Wis.), the first out lesbian elected to the Senate, and Sen. Kyrsten Sinema (D-Ariz.), the first open bisexual elected to the Senate.

One of seven openly gay ambassadors in the Obama administration, Baer as U.S. ambassador to OSCE was charged with deescalating tensions in Europe during the Ukraine crisis in 2014.

Previously, Baer served as deputy assistant secretary for the Bureau of Democracy, Human Rights & Labor under Hillary Clinton when she was secretary of state. Baer worked on international LGBT issues, including the integration of LGBT human rights abuses in the State Department’s annual human rights report.

In a campaign video announcement titled “Driving Change,” Baer touts his foreign policy experience at OSCE as well his relationship with his spouse and their dog.

It’s not the first time Baer has pursued a run for Congress. In 2017, Baer launched a campaign to run for a U.S. House seat representing Colorado’s 7th congressional district. But Baer later dropped that bid after incumbent Rep. Ed. Perlmutter (D-Colo.) changed his mind and decided to keep the seat he said he’d vacate.

By seeking the Democratic nomination to run for U.S. Senate, Baer is potentially challenging Sen. Cory Gardner (R-Colo.), one of the most vulnerable senators up for election in 2020. According to the Democratic Senatorial Campaign Committee, Gardner is currently polling eight points behind a generic Democratic on the ballot.

In an interview with the Denver Post, Baer touted his foreign policy experience in explaining why he’d be superior to the sitting Republican incumbent currently representing Colorado.

“Cory Gardner sits on the Foreign Relations Committee,” Baer said. “I think one of the things I offer as a candidate going up against him is that I can go toe-to-toe with Cory Gardner on foreign policy issues.”

But Baer is one of seven Democrats seeking their party’s nomination to run against Gardner and it remains to be seen if Baer will claim victory. The filing deadline and primary for Colorado aren’t yet scheduled.