Sen. Cory Booker (D-N.J.) on Monday endorsed former Vice President Joe Biden for the 2020 Democratic presidential nomination, adding the voice of another former presidential candidate to Biden’s campaign.

Booker, who quit the crowded Democratic race in January, announced his endorsement on Twitter.

“The answer to hatred & division is to reignite our spirit of common purpose,” Booker wrote. Biden “won’t only win ― he’ll show there’s more that unites us than divides us. He’ll restore honor to the Oval Office and tackle our most pressing challenges.”

The answer to hatred & division is to reignite our spirit of common purpose.@JoeBiden won’t only win - he’ll

show there's more that unites us than divides us.



He’ll restore honor to the Oval Office and tackle our most pressing challenges.



That’s why I’m proud to endorse Joe. pic.twitter.com/RcsnZs5mfQ — Cory Booker (@CoryBooker) March 9, 2020

Booker adds to the flood of high-profile endorsements since last week that have helped revive Biden’s once-struggling primary campaign. Biden’s backers include numerous former 2020 Democratic presidential candidates. Sen. Kamala Harris (D-Calif.), who suspended her campaign in November, endorsed the former vice president on Saturday.

Harris and Booker will join Biden at his campaign rally in Detroit on Monday evening, reported Politico.

Pete Buttigieg and Sen. Amy Klobuchar (D-Minn.) threw their support behind Biden ahead of Super Tuesday last week. Biden won 10 of the 14 states up for grabs during the jam-packed day of primary contests. Mike Bloomberg quit the race the day after Super Tuesday and endorsed Biden.

Booker is up for reelection in the Senate in November. After dropping out of the presidential race, he repositioned some of his presidential campaign apparatus to help with his Senate reelection, The New York Times reported.

The endorsements from Harris and Booker, two of the most prominent Black members of Congress, followed Sen. Bernie Sanders’ (I-Vt.) failure to win over the majority Black voters in some states on Super Tuesday.

Biden surpassed Sanders by 40 percentage points or more among Black voters in Texas and North Carolina. In Alabama and Virginia, Biden had the support of about 7 in 10 Black voters.

Though Sanders has performed well with young Black voters, people younger than 30 did not account for more than 20% of the electorate in any state on Super Tuesday, reported the Times.

“It’s a time for us to beat Donald Trump and it became very clear to me that Joe Biden is the right person to do that,” Booker said during an interview on “CBS This Morning” on Monday. “It’s about time that we start unifying as a party.”

Despite criticizing Biden on the campaign trail over his role in passing the controversial 1994 crime bill, Booker said Monday that he’s “enthusiastic” about the former vice president’s proposals for criminal justice and economic reform.

“I think a lot of people are waking up to the reality: African American voters ... have played a pivotal role in choosing the Democratic nominee,” Booker told CBS News. “I’m happy about the diversity of our nation. I’m happy to see the coalitions that Joe Biden is building.”