Cory Booker led a parade of prominent African Americans in testifying to Congress on the need for reparations for descendants of slaves on Wednesday and argued amends were needed to get rid of a 'stain' on the country.

'We, as a nation, have not yet to truly acknowledge and grapple with the racism and white supremacy that tainted this country's founding and continues to cause persistent and deep racial disparities and inequality,' Booker, who's running for the 2020 presidential nomination, said.

'The stain of slavery was not just inked in bloodshed but in policies that have disadvantaged African Americans for generations,' he noted.

Protest: Members of the New Black Panther Party rallied outside the Congressional committee room where House members heard evidence on reparations

Presence: Around a dozen members of the New Black Panther Party were outside the committee room while the hearing went on

Cory Booker led a parade of prominent African Americans in testifying on the need for reparations for descendants of slaves

Actor Danny Glover, right, and author Ta-Nehisi Coates, left, testify about reparations issue

Booker, actor Danny Glover, and author Ta-Nehisi Coates were among those testifying at the nearly 3-hour hearing on Capitol Hill on Juneteenth, the day that makes the anniversary of the Emancipation Proclamation that freed the slaves.

'I sit here as the great grandson of a former slave who was freed by the Emancipation proclamation. I had the fortune of meeting him as a small child,' Glover told the lawmakers.

The hearing, launched by Democrats, was the first one to be held on the subject of reparations in more than a decade, putting the spotlight on the debate about whether the government should compensate descendants of slaves.

Outside the committee room members of the New Black Panther party rallied; inside there were clashes between Democrats and Republicans and one GOP witness spoke through boos.

'It's about time we find the common ground and the common purpose to deal with the ugly past and make sure that generations ahead do not have to continue to mark disparities,' Booker said.

Booker has sponsored legislation in the Senate to study the reparations issue.

The other five senators seeking the Democratic nomination - Kamala Harris, Amy Klobuchar, Kirsten Gillibrand, Bernie Sanders, and Elizabeth Warren - have signed on co-sponsors.

In his opening remarks at the hearing, Rep. Steve Cohen, chairman of the subcommittee, noted it took 100 years after the end of slavery to end Jim Crow Laws with the Civil Rights Act of 1964 and the Voting Rights Act of 1965.

And Coates, the author who reignited the reparations debate with his essay 'The Case for Reparations,' published in The Atlantic magazine in 2014, said reparations was more about making amends.

'The matter of reparations is one of making amends and direct redress but is also a question of citizenship,' he said.

He also said reparations could take the form of financial compensation.

'I don't believe we should rule out cutting checks,' he said.

Democratic Rep. Sheila Jackson Lee, the House sponsor of legislation to study the reparations issue, said black Americans 'are the only group that can singularly claim to have been slaves under the auspices of the United States government.'

She said the hearing 'is not a symbolic action,' but about legislation that should be signed into law.

'I just simply ask: Why not and why not now?' she said to the packed hearing room, which had people lined up outside waiting to get in.

'Slavery is the original sin. Slavery has never received an apology,' she noted.

Republicans invited writer Coleman Hughes and also Burgess Owens, a former Oakland Raiders football player and Super Bowl champion, who recently wrote a Wall Street Journal editorial eschewing reparations.

Hughes, who at times testified over boos from the audience, said black people don't need 'another apology,' but safer neighborhoods, better schools, a less punitive criminal justice system and better health care.

'None of these things can be achieved through reparations for slavery,' said Hughes, who says he is the descendant of blacks enslaved at Thomas Jefferson's Monticello.

Rep. Shelia Jackson Lee is sponsoring legislation to study the reparations issue

Crowds lined up in front of the hearing room

Opposition: Republicans called former NFL star Burgess Owens (left) and writer Coleman Hughes to give evidence. Hughes, who at times testified over boos from the audience, said black people don't need 'another apology'

Campaigners: Members of the New Black Panther Party were present to make the case for reparations

Black power: The members of the New Black Panthers gave the clenched fist salute outside the committee room

Republicans also used evidence from Owens to attack the Democrats over the party's historical positions on slavery and Jim Crow, and opposition to civil rights legislation.

Texas Republican Louie Gohmert said in reference to evidence from Democratic members of Congress including Booker: 'Three-fourths of the opposition to the 1964 Civil Rights Act came in the House from the Democrats while 80% of the nay votes in the Senate came from the Democrats.

'There is no reference to Democratic platforms that either supported segregation outright or were silent on the subject. There were twenty from 1868 – 1948.

'No reference to Jim Crow laws nor is there a reference to the role the Democrats played in creating them.'

And he asked Owens: 'What do you think your great grandfather Silas [a slave] would have said to someone who claims, "the Republicans are the party of racism?"'

The House Judiciary Subcommittee on the Constitution, Civil Rights and Civil Liberties held the hearing on Jackson Lee's legislation, which calls for a commission to 'study and develop reparation proposals for African-Americans,' including a formal apology by the U.S. government.

House Majority Leader Steny Hoyer told reporters Wednesday morning the House would hold vote on whatever proposal came out of committee.

'It will get a vote if it comes out of the committee; I expect it to come out of the committee,' he said.

But the legislative process is long and cumbersome - the legislation has to be heard in a hearing, be marked up by the committee, and then passed out of that committee before it goes to the House floor.

Then it would have to pass the Senate and be signed by the president.

But Senate Republican Leader Mitch McConnell indicated on Tuesday the subject would never come up for a vote in the upper chamber.

He argued the U.S. has dealt with the sin of slavery in many ways, including electing an African American president - Barack Obama.

'I don't think reparations for something that happened 150 years ago for whom none us currently living are responsible is a good idea,' McConnell said.

'We've tried to deal with our original sin of slavery by fighting a civil war, by passing landmark civil rights legislation. We elected an African American president.'

'It would be hard to figure out who to compensate' for slavery, he said, adding: 'No one currently alive was responsible for that.'

Meanwhile, Obama tweeted his thoughts on Juneteenth, writing: 'On Juneteenth, we celebrate our capacity to make real the promise of our founding, that thing inside each of us that says America is not yet finished, that compels all of us to fight for justice and equality until this country we love more closely aligns with our highest ideals.'

The topic of reparations has become a hot one among Democrats in the 2020 presidential race.

Several of the candidates have pledge to study the issue or make some kind of amends, including Beto O'Rourke, Kamala Harris, Elizabeth Warren, and Julián Castro.

And President Donald Trump released a statement to mark Juneteenth.

'For millions of African Americans, Juneteenth has served as an opportunity to celebrate the fundamental truth that all people are created equal and that liberty is a right endowed by our Creator,' he said.

'Across our country, the contributions of African Americans continue to enrich every facet of American life. This Juneteenth, as we vow always to uphold the God-given rights of all Americans, we pay tribute to the indomitable spirit of African Americans.'

Additionally, Republican National Committee Chairwoman Ronna McDaniel said: 'As we honor 400 years of African American history, may we reflect on the resilience and cultural contributions of the African American community. In reflecting on the wrongs of our nation's past, we are reminded of the importance of equal opportunity for all.'

While reparations has been moving toward the mainstream of the Democratic Party, the idea remains far from widely accepted, both among Democrats and the public at large.

In a Point Taken-Marist poll conducted in 2016, 68 percent of Americans said the country should not pay cash reparations to African American descendants of slaves to make up for the harm caused by slavery and racial discrimination. About 8 in 10 white Americans said they were opposed to reparations, while about 6 in 10 black Americans said they were in favor.