Out Maryland State Senator Richard Madaleno, a Democrat from Montgomery County, on Monday announced he's running for governor.

Madaleno made his official announcement at the University at Shady Grove in North Potomac.

“I'm running for governor and I'm going to win,” Madaleno said.

When first elected to the Senate in 2006 after serving a term in the House of Delegates, Madaleno, 52, became the chamber's first openly gay member. He was a strong supporter of the same-sex marriage bill then-Governor Martin O'Malley signed in 2012 and introduced a transgender rights bill that became law in 2014. Madaleno and his husband Mark are raising two children.

In his announcement speech, Madaleno described himself as a “proud husband and a loving father.”

“I will never back down on civil rights, on LGBTQ rights, on workers' rights, on women's rights on voting rights,” he told the crowd. “Our rights cannot and will not be sacrificed with Rich Madaleno as governor.”

Other Democrats vying to challenge Governor Larry Hogan next year include Prince George's County Executive Rushern Baker, former NCAAP President Ben Jealous and former State Department official Alec Ross.

Madaleno declared that he is the only Democrat who can beat Hogan next fall.

“I will win because there is no other candidate in this, including the incumbent, who brings my track record of leadership and real results for the people of Maryland,” Madaleno said.

He also pledged to hold President Donald Trump “accountable for the damage being done to our state and to our country.”

According to a poll conducted last year, Hogan, Maryland's second Republican governor in nearly 50 years, has a strong (70%) approval rating, even among Democrats (53%).