Montana Gov. Steve Bullock (D) is running for president, he announced on Tuesday.

We need to defeat Donald Trump in 2020 and defeat the corrupt system that lets campaign money drown out the peoples voice, so we can finally make good on the promise of a fair shot for everyone, Bullock said in a campaign launch video .

Bullock, 53, joins a crowded field of more than 20 Democrats seeking the opportunity to challenge Trump. He is the only Democratic candidate who has won a statewide office in a state that went for the president in 2016 : In his reelection that year, Bullock won by 4 percentage points even as Trump took Montana by 20.

The two-term governor , who has served in that office since 2013, would not be able to run for reelection next year due to term limits.

The Montana native and former state attorney general formed a political action committee, Big Sky Values PAC , in 2017, according to MTN News . The PACs website boasts that Bullock has a record of pushing a strong progressive agenda in a deep red state.

Working with a Republican legislature, Bullock expanded Medicaid in the state and passed an earned income tax credit. And last year, after the Federal Communications Commission repealed net neutrality, Bullock signed an executive order making Montana the first state to establish its own net neutrality rules.

Bullock has made fighting dark money in politics a focus of his career. As state attorney general in 2012, he fought against the Citizens United decision , a Supreme Court ruling that allowed corporations to spend unlimited sums of money on elections. Later as governor, Bullock worked with legislators in 2015 to pass a bill to require anonymous donor groups to disclose spending in the states political campaigns.

Bullock will formally announce his run Tuesday afternoon with an event at his alma mater, Helena High School. Hell make a three-day trip to Iowa this weekend, the start of a campaign that will focus heavily on the first-in-the-nation caucuses.