Sen. Cory Booker announced a bill Monday to form a commission to recommend reparations for slavery, taking the reins of one of the most intriguing and controversial agenda items from the 2020 campaign.

Mr. Booker becomes the highest-profile lawmaker to sign onto reparations legislation, saying it could solve persistent racism and discrimination that have been built into the system for decades, leading to disparate outcomes for all black Americans.

“This bill is a way of addressing head-on the persistence of racism, white supremacy, and implicit racial bias in our country,” he said. “It will bring together the best minds to study the issue and propose solutions that will finally begin to right the economic scales of past harms and make sure we are a country where all dignity and humanity is affirmed.”

Mr. Booker is part of the massive 2020 Democratic field, where the conversation about reparations is already heating up.

A reparations bill has been introduced in the House for years, but had attracted limited support.

This year, though, Rep. Tulsi Gabbard, another Democrat running for president, signed on as a co-sponsor.

Former Rep. Beto O’Rourke, who did not sign on while he was in Congress this decade, now says on the campaign trail he would support a commission. That’s a reversal from last month, when he said he didn’t favor reparations.

Mr. Booker is teaming up with Rep. Sheila Jackson Lee, the Texas Democrat who took over the main reparations legislation after former Rep. John Conyers Jr., the longtime chief sponsor, left Congress in 2017 amid a MeToo-fueled inquiry into his behavior.

Mr. Booker on the campaign trail had complained about how the reparations conversation was playing out, saying it was being turned into a check-box issue for candidates and activists.

In the past, he’s promoted legislation aimed at creating a savings account for children born in the U.S., with taxpayers chipping in more money for those on the lower end of the income scale.

Every child would get a $1,000 starter payment, but a child born to a family below the poverty line would receive $2,000 a year, while a child born to a family making 225 percent of the poverty level would get $500. Families making more than 500 percent of the poverty level would not receive any annual payments.

Mr. Booker had pitched that idea as a viable way of closing the wealth gap between black and white families.