California Attorney General Kamala Harris on Tuesday became the first major candidate to formally declare her intention to run for the Senate seat being vacated by Sen. Barbara Boxer. She will enter the race as the perceived front-runner in what is expected to be a crowded field of Democrats vying for the state’s first open Senate seat in more than two decades.

I hope you will join me on this journey. We will do incredible things together. https://t.co/HMg9by6v1Z #CASen — Kamala Harris (@KamalaHarris) January 13, 2015

I’m excited to share with you that I’m launching my campaign to represent the people of California in the United States Senate,” she said in a message to supporters posted on her campaign website . “I will be a fighter for the next generation on the critical issues facing our country. I will be a fighter for middle class families who are feeling the pinch of stagnant wages and diminishing opportunity. I will be a fighter for our children who deserve a world-class education, and for students burdened by predatory lenders and skyrocketing tuition. And I will fight relentlessly to protect our coast, our immigrant communities and our seniors.”

Harris has been closely watched since Boxer announced her retirement last week, and especially after Lt. Gov. Gavin Newsom, who was considered another top potential contender, announced Monday that he would not run.

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Harris is one of the few politicians in California with a statewide profile and is widely seen as one of — if not the — most formidable candidates for Boxer’s seat. Advisers to Harris told multiple news outlets Monday that she was prepared to enter the race.

The campaign arm of Senate Democrats, which is typically heavily involved in selecting the party’s nominees, signaled strong support for Harris moments after her announcement. “With strong candidates like Kamala Harris Democrats remain confident that we’ll hold this seat and continue Barbara Boxer’s long history of fighting for California. The DSCC will continue to monitor the California Senate race closely,” Democratic Senatorial Campaign Committee spokesperson Justin Barasky said in a statement to reporters.

She would likely have a national support base and is said to be favored by powerful national Democratic groups like EMILY’s List.

Later on Tuesday, California Democratic Rep. Loretta Sanchez announced that she too is “seriously considering running” for the Senate seat next year. “For the past 18 years, I have focused on putting California’s working families first. From immigration reform to affordable health care to funding quality education, I have advocated for policies that give all families the same access to the American Dream. Californians deserve a strong voice in Washington and I have never been afraid to speak up,” she said in a statement.

Sanchez has long harbored an interest in running for Senate. A member of the moderate Blue Dog Democrat coalition, she could find support in the ideological center if the field skews more liberal.

And billionaire climate activist Tom Steyer, who has been eying a run, wrote an op-ed in the Huffington Post Tuesday evening hinting at his rationale for a run. “Holding office is a sacred trust in our society, and I am honored that so many colleagues and friends have encouraged me to consider entering this race. One thing is clear: Washington needs to be shaken up, and we need climate champions who will fight for the next generation,” he wrote.

“California Democrats are blessed to have a deep bench of talent, and I will decide soon based on what I think is the best way to continue the hard work we’ve already started together to prevent climate disaster and preserve American prosperity,” he added.

Former Los Angeles Mayor Antonio Villaraigosa this weekend announced he too is considering a bid. Villaraigosa is well known in state and nationally after serving as a surrogate for Barack Obama’s 2012 reelection bid and chairman of the Democratic National Convention. But he’ll face some opposition from organized labor over his negotiations as mayor with city worker unions.

State Treasurer John Chiang is also considering a bid, according to the Los Angeles Times.

Harris, a former prosecutor in Alameda County and San Francisco, capture the attention of national Democrats when she ran for the state’s top law enforcement position in 2010, overcoming concerns she was too liberal to win statewide. Harris advocates a “Smart on Crime” philosophy, which takes a more holistic and economic approach to crime than a narrow punitive approach, as outlined in a 2009 book ahead of her run.

The daughter of an Indian mother and a Jamaican father, Harris was the first female, first African-American, and first Asian-American attorney general of the Golden State.