WASHINGTON — Cory Booker’s jaw tensed, the muscles in his face visibly flexing.

He was about to step to a lectern in the basement of the Capitol, alongside other black Democratic members of Congress and the party’s House and Senate leaders. Booker, a former college football player, wore a glare like an athlete about to run through the stadium tunnel.

“We in America are one precious, same nation, but we have a wildly different set of experiences with the police, where black Americans live in fear of police interactions,” Booker began Monday as he and fellow Democrats unveiled a police reform bill that could pass the House this month. “Empathy and sympathy and words of caring for those who have died and suffered are necessary, but it’s not enough.... We must change laws and systems of accountability.”

For Booker, a New Jerseyan and former presidential candidate, the police killing of George Floyd and ensuing public outcry have created an opening for massive change on the type of civil rights issue that has driven his Senate career and shaped his childhood.

It’s also a head-snapping turn. Booker built his presidential run on addressing issues of racial inequality and healing divides, but he gained little traction and dropped out in January, before the first votes were cast.

Now, those same issues are at the center of the national debate, and Booker is at the front of Democrats’ push for police reform.

Standing alongside a statue of Frederick Douglass in the Capitol’s Emancipation Hall, he recently led Senate Democrats in 8 minutes and 46 seconds of silence in remembrance of Floyd, marking the time a Minneapolis police officer knelt on Floyd’s neck. Booker was the lead guest on NBC’s Meet the Press on Sunday, carrying the Democratic message about the effort in Congress.

He helped write the reform bill and is now lobbying Republican colleagues in the GOP-controlled Senate.

‘I owe a debt’

“This is very personal to me because of my own life experiences, and that of so many people that I know,” Booker said in an interview. “It’s personal to me because I owe a debt. My even moving into New Jersey was marked by violence, and so I owe a debt, and I’m going to do everything I can. And it’s not just to the struggles of African Americans, it’s to all those people who have been struggling to make this country live up to its promise.”

The former mayor of Newark, Booker is one of only three black senators, and often notes that he’s the only senator who lives in a low-income community made up mostly of people of color.

As mayor, though, Booker touted tough-on-crime policing and clashed with the American Civil Liberties Union, which tallied 418 misconduct allegations against Newark police, including excessive force complaints, and sparked a Department of Justice investigation. It found police stopped black people 2.5 times more often than white residents.

He later expressed regret for his initial approach as mayor and embraced reforms even before the investigation was complete, said Udi Ofer, the former head of the New Jersey ACLU. Booker has made criminal justice his main focus on the Senate, and played a key role in major sentencing reform enacted in 2018.

“Today Sen. Booker is one of the greatest champions of criminal justice reform in the Senate,” said Ofer, now the ACLU’s deputy national political director. “I think a lot of this dates back to the lessons learned from his experience as mayor.”

Booker’s parents were active in the civil rights movement and took part in a sting to fight housing discrimination so they could buy a home in suburban Harrington Park, where Realtors tried to exclude them.

Their story became the central thread of Booker’s presidential stump speech, delivered last year to mostly white crowds in Iowa churches and largely black audiences at South Carolina colleges.

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The speech would peak with a story about a white lawyer in New Jersey who saw news reports about the police assault on civil rights marchers in Selma, Ala., and was inspired to volunteer. He was assigned to a housing case involving Cary and Carolyn Booker, the senator’s parents.

When Booker closed the loop, his audience would inevitably fall to a hush.

But he didn’t win enough support, for a variety of reasons. The black voters he courted mostly stuck with Joe Biden, and some white Democrats openly worried that nominating a black man would help President Donald Trump sow racial division.

“Fundamentally, black voters made a judgment that in order to defeat a president whose power was based on white supremacy, that we needed a white candidate,” said Steve Phillips, a Democratic fund-raiser who attended Stanford University with Booker and supported his campaign.

But Phillips said Booker’s personal experience and understanding of history now fit the moment.

“Of almost all the national political leaders, the person who best understands and can articulate the challenges of racial equality and injustice in this country is Cory,” said Phillips, who leads an organization and hosts a podcast, both called Democracy in Color. “It’s drawing those connections and painting the picture of the context and history of the current situation.”

In a recent Senate speech, Booker, 51, read an article he wrote in the Stanford student newspaper in 1992, after four Los Angeles police officers were acquitted of beating Rodney King. At 6-foot-3 and 230 pounds, Booker wrote, he was same size as King, and recounted being followed by mall security and pulled over and confronted by six police because he “fit the description” of a car thief.

» READ MORE: How Cory Booker's 'failed' football career at Stanford helped shape his political future

“That was three decades ago," Booker said. “And I wish I could stand here and tell you that much has changed.... I wish I could tell you that that was the end of names becoming household words, but it has not.”

New York Sen. Chuck Schumer, the Senate Democratic leader, said, “Cory is one of the most passionate and effective leaders in our country, and he’s drawn on these strengths — and his own lived experience — to help lead our caucus on this issue.”

Support for reform — but will it happen?

The moment appears ripe for police reform.

Polls show a drastic shift in public opinion: 69% of Americans see Floyd’s killing as an indicator of broader problems with law enforcement, according to a new Washington Post-Schar School survey. That’s up from 43% when a similar question was asked about black men killed by police in 2014.

Democrats, who control the House, are poised to quickly pass their bill. It would make it easier to prosecute police misconduct and would ban choke holds. It would create a national registry to track misconduct and give the Department of Justice more power to investigate police departments.

Senate Republicans are crafting their own measure, led by the chamber’s only black Republican. Tim Scott of South Carolina. Some bipartisan support will be needed to pass anything through the Senate.

And it’s unclear what reforms, if any, Trump will endorse, as he frequently tweets about “LAW & ORDER" and accuses Democrats of extremism amid some activists’ calls to “defund police.” The Democratic bill does not take that step in any of its various meanings.

Booker has had at least one significant success with Trump and Republicans, working with both to pass the criminal justice overhaul in 2018.

“I’ve been in the Senate now for a full term and I’ve seen impossible things become possible,” said Booker, who is up for reelection this year and faces a longshot primary challenge from liberal activist Lawrence Hamm, who has criticized Booker’s policing record in Newark.

Not that long ago, however, many people saw another tragedy — the 2012 massacre of schoolchildren in Newtown, Conn. — as a national turning point that seemed destined to lead to tougher national gun laws. Nothing happened.

Booker’s challenge is to help this moment avoid the same fate.