Rep. Barbara Lee (D-CA) announced her bid to lead the House Democratic Caucus Monday, formally launching an effort to fill the leadership position that will soon be left vacant due to the surprise primary loss of Rep. Joe Crowley (D-NY).

Excited to announce I’m running for House Democratic Caucus Chair. My candidacy is based on three beliefs: the strength of our caucus lies in our diversity, we are at our best when everyone has the opportunity to contribute, and we must work to improve the lives of all people. — Barbara Lee (@BLeeForCongress) July 23, 2018

“When you look at the history of the Democratic Party and the Democratic leadership, African-American women … we’ve been the backbone of the Democratic Party — we should be in the face of leadership also,’’ Lee told Politico for an article on her announcement.

According to Politico and the Washington Post, Lee would be the first black woman to hold a leadership position in either major party.

“The strength of our caucus lies in our diversity of experiences and ideas,’’ the congresswoman wrote in a letter to colleagues announcing her bid Monday. “Whether it’s working across the aisle to enact HIV/AIDS laws, or bringing the Sanders and Clinton campaigns together behind a cohesive and progressive Democratic platform, my career has been dedicated to finding common ground and delivering results.”

Crowley’s astonishing primary upset by Alexandria Ocasio-Cortez last month unexpectedly stirred up the race to lead the Democratic caucus. With the Queens County Democratic Party leader on his way out, Lee will face off against current caucus vice chair Rep. Linda Sánchez (D-CA) for the soon-to-be-vacant caucus leader position.

In 2016, Sánchez beat Lee by two votes to become vice chair. Sánchez announced her bid for caucus chair last week.

In late June, soon after Crowley’s surprise upset, Lee told the Post: “If this were not an open seat, I’d be making a different calculation. But things move fast around here, and I didn’t want to wait until November to start looking at this.”

The Democratic caucus chair comes behind the minority leader, the minority whip and the assistant minority leader in the current House Democratic hierarchy. If Democrats win back the House in 2018, the speaker of the House — whoever that may be, though current Minority Leader Nancy Pelosi (D-CA) has said she would run again for the role — will add another position atop the list.

Lee, known for being the historic sole vote against the Authorization of Military Force just three days after the September 11, 2001 attacks, comes from a wing of the Democratic Party that isn’t currently represented in House leadership.

Last year, Lee’s amendment to sunset that AUMF unexpectedly received bipartisan support and was voted out of the House Appropriations Committee for a House-wide vote. A few weeks later, House Speaker Paul Ryan (R-WI) stripped it from the annual defense appropriations bill “in the dead of night,” in Lee’s words.

AshLee Strong, a spokesperson for Ryan, told TPM at the time that the amendment “endangers our national security.”

Lee already has the endorsements of a number of lawmakers, among them Reps. Jan Schakowsky (D-IL) and Ro Khanna (D-CA).

“I am proud to support Barbara Lee for conference chair. I will be rallying my colleagues in the progressive caucus for her and also incoming freshman whose campaigns I have helped,” Khanna told The Intercept earlier this month. “I have often said that if John F. Kennedy were writing ‘Profiles of Courage’ today, there would be a chapter on Barbara Lee. Her vote in opposing the blank check to war is one of the most courageous acts of modern time.”

While Ocasio-Cortez on Sunday left open the possibility she will support Pelosi to lead House Democrats in 2018, she wondered aloud to the Washington Post in June, “Is Barbara Lee available?”