Rep. Barbara Lee of California has officially announced her bid for the U.S. Senate seat being vacated by retiring Sen. Dianne Feinstein. Lee, a long-time Congresswoman, is joining a crowded field of candidates for the seat.

Lee, who has served in Congress since 1998, announced her campaign on Tuesday. In a statement, she said: “I am running for the U.S. Senate to fight for our shared values and to stand up for the people of California. It’s time for a new generation of leadership in the Senate.”

Lee has been an outspoken advocate for progressive policies, including criminal justice reform, health care for all, and environmental protection. She has also been a vocal opponent of President Donald Trump’s policies.

Lee will face a number of other candidates in the Democratic primary, including California Secretary of State Alex Padilla and California State Senator Scott Wiener. The winner of the primary will face off against Republican candidate and former U.S. Ambassador to the United Nations, John Bolton, in the general election.

The race is expected to be a closely watched one, as the outcome could decide the balance of power in the Senate. California is one of the most populous states in the country, and the result of the election could have a significant impact on the future of the nation.