Democratic Senator Elizabeth Warren, a progressive firebrand who has shaped a political career around taking on Wall Street, endorsed Hillary Clinton’s White House bid after withholding support for months during the Democratic presidential contest between Clinton and rival Bernie Sanders.

Warren announced her endorsement on MSNBC’s “Rachel Maddow Show” tonight.

“I am ready to get into this fight and to work my heart out for Hillary Clinton and to make sure that Donald Trump doesn’t get anywhere near the White House,” Warren said.

The move by the first-term Massachusetts senator, who many had urged to enter the 2016 race herself, provides progressive Democrats with a strong signal to rally around the party’s presumptive nominee. It came on the same day President Barack Obamaformally endorsed Clinton in a bid to unify Democrats following a White House meeting with Sanders. Vice President Joe Biden also signaled his support in a speech on Thursday, saying “God willing,” the next president would be Clinton.

Warren’s endorsement bolsters Clinton after a protracted campaign against Sanders that exposed her vulnerabilities as a candidate and sparked divisions among Democrats. Warren’s crusade against big financial institutions is particularly helpful to Clinton, who Sanders has accused of being too close to big banks and a beneficiary of paid speeches to institutions including Goldman Sachs Group Inc.

Clinton says she is looking forward to having Warren’s “good advice and counsel,” as the liberal senator steps up her attacks on Republican standard-bearer Donald Trump.

Clinton plans to consult with Warren and others about how to implement a Wall Street regulation plan, and has spoken to the senator in the “last few weeks,” she said in an interview with Bloomberg Politics today.

‘Good Advice’

“We’ve stayed in touch over the campaign and I’m very much looking forward to having her good advice and counsel as we move to the general-election campaign,” Clinton said. “I have the highest regard for her.” Clinton said she’d particularly focus on guarding the Consumer Financial Protection Bureau and Dodd- Frank rules, which are important to Warren.

Clinton made history this week when she became the first woman to lead the ticket of a major political party. She reached the 2,383 pledged delegates and superdelegates needed to become the presumptive Democratic presidential nominee, according to an Associated Press release before the June 7 primaries in California, New Jersey, New Mexico and three other states.

A former Harvard Law School professor, Warren was a frequent witness at congressional hearings during the 1990s, when she warned about the causes of rising indebtedness among middle- and lower-income Americans that fueled a growing number of bankruptcy filings. She later led a five-member congressional oversight panel to oversee implementation of the $700 billion financial bailout that was approved in 2008, and also proposed the creation of what became the Consumer Financial Protection Bureau.

Those roles helped give her outsized influence in the Senate after she won her seat in 2012. In the chamber and as a member of the Banking Committee, she’s argued against a political system she says is rigged in favor of large banks and other special interests, and against middle-class and low-income families.

Activists had sought early on to enlist her to challenge Clinton but the senator took herself out of consideration. Sanders, who continues to campaign for the Democratic nomination, became a proxy of sorts for the effort to draft Warren.

Warren said on MSNBC that wavering progressives shouldn’t write in Sanders or vote for third parties, since Trump was underestimated by Republicans and represents a “genuine threat” to the country.

Vice President

Some top Democrats, including Senator Dick Durbin of Illinois, have said Warren is among the people Clinton should consider as a possible running mate.

Warren said she’s heard nothing from Clinton about serving as vice president. Asked if she’d be ready to step in as commander-in-chief if she were Clinton’s running mate, Warren said yes.

Clinton said in a separate interview with Politico on Thursday that Warren is “qualified” to be vice president. She has previously said the U.S. may be ready for a two-woman ticket this year and that she will focus on qualifications in her running-mate search.

Warren attacked Trump in an address tonight over comments he made about a federal judge. Trump had said that U.S. District Judge Gonzalo Curiel, who is overseeing lawsuits against Trump University, is biased against Trump, citing the judge’s Mexican descent.

“Donald Trump chose racism as his weapon, but his aim is exactly the same as the rest of the Republicans,” Warren said at the speech in Washington. “Pound the courts into submission to the rich and powerful.”