Democratic presidential contender Cory Booker introduced legislation Monday to establish a commission to study reparations for a slavery - a hot topic in the battle to take on President Donald Trump next year.

'I am proud to introduce legislation that will finally address many of our country's policies - rooted in a history of slavery and white supremacy - that continue to erode Black communities, perpetuate racism and implicit bias, and widen the racial wealth gap,' Booker wrote on Twitter Monday.

The issue has gathered steam on the Democratic presidential campaign trails as the big field of candidates courts the powerful African-American voting bloc.

Democratic presidential contender Cory Booker introduced legislation to set up a commission to study reparations for a slavery

More and more contenders are backing a type of study or commission to examine whether reparations should be made to African Americans whose ancestors were held in bondage.

A reparations bill sponsored by Rep. Sheila Jackson Lee - that calls for a commission to study the issue - is all but certain to pass in the House of Representatives now that Democrats control the chamber.

Booker is proposing a companion piece of legislation that will explore reparations proposals.

He supports Jackson Lee's legislation as does Sen. Elizabeth Warren.

The topic of reparations came up repeatedly last week at Rev. Al Sharpton's National Action Network conference.

Sharpton is one of the most prominent African American activists in the country and his support is seen as crucial for any candidate courting black voters.

Bernie Sanders, who previously said he did not support monetary reparations for slavery in the past, told Sharpton last week he is willing to back a study on subject should he become president.

'If the House and Senate passed that bill, of course I would sign it,' the independent senator from Vermont said.

Sanders had come under criticism for his lack of support on the issue.

Democratic presidential contender Julian Castro attacked him on the issue last month, asking why he's not willing to write a check to descendants of slaves when he's willing to spend on Medicare for all.

'Why wouldn't we be bold on reparations?' he asked at the South by Southwest festival.

Sanders had told ABC's 'The View' earlier last month that more attention needs to be paid to 'distressed communities' but would not commit to fiscal reparations.

Bernie Sanders, who previously said he did not support monetary reparations for slavery in the past, said last week he is willing to back a study on subject should he become president

Democratic presidential contender Julian Castro whacked at rival Bernie Sanders over reparations for the descendants of slaves

'I think what we have got to do is pay attention to distressed communities: black communities, Latino communities, and white communities, and as president, I pledge to do that,' Sanders said.

Pressed on the issue, Sanders would not say money should be paid to descendants.

'I think that right now, our job is to address the crises facing the American people and our communities, and I think there are better ways to do that than just writing out a check,' he said.

But he gave a stronger sign of report to Sharpton and his crowd of black activists last week.

Beto O'Rourke also announced at the conference he would sign into law legislation calling for a commission to study the issue.

'Yes,' he told attendees. 'Absolutely, I would sign that into law.'

O'Rourke recounted a conversation with Bryan Stevenson, the executive director of the Equal Justice Initiative, and said that 'foundational to reparations is the word repair, foundational to repair is the truth.'

Beto O'Rourke also said he would sign legislation to study reparations to Black Americans

Elizabeth Warren has called for Massachusetts has called for a 'national, full-blown conversation' on the issue of reparations

Sen. Kamala Harris also said she would sign such legislation into law

He had previously hinted he would not support reparations.

'I don't believe ... that [reparations] should be the primary or initial focus of the conversation,' he said campaigning in New Hampshire last month.

Sen. Kamala Harris also said she would sign such a bill into law.

Harris told Sharpton: 'When I am elected president, I will sign that bill.'

Warren said the same: 'Yes. I would. I already support that bill.'

The senator from Massachusetts has called for a 'national, full-blown conversation' on the reparations issue.

Sen. Kirsten Gillibrand also said she would sign the legislation.

'This is a conversation that is long overdue. So, I want to let you know where I stand. I firmly support Congresswoman Jackson Lee's bill to study reparations. As president, I would advocate to Congress to pass that bill, and I would sign that commission into law,' she said.

Fifty-two percent of the African-Americans surveyed in a 2015 CNN-Kaiser poll supported cash payments to the descendants of slaves.

But 89 percent of the white Americans polled opposed the idea.

The United States has handed out reparations in the past including to Japanese-Americans put in internment camps during World War II.