Protesters are planning to return to Lincoln Park Friday to denounce and urge the removal of a statue of Abraham Lincoln, paid for by people who had been enslaved, that celebrates emancipation and depicts the president standing over a kneeling African American man.

Federal and D.C. law enforcement on Thursday erected barriers around the Emancipation Memorial in the Capitol Hill neighborhood in advance of demonstrations. Throughout the evening, those who want the statue to remain and those who want to see it removed debated. Few were swayed, and those arguing for it to come down vowed to return Friday, though it was unclear whether they would seek to topple it or simply rally in favor of a more orderly removal.

D.C. Mayor Muriel E. Bowser (D) argued for the latter approach at a news conference Thursday, saying the city should debate the fates of statues and “not have a mob decide they want to pull it down.” On Monday, police broke up an effort to tear down a statue of President Andrew Jackson in Lafayette Square.

Critics say the Emancipation Memorial — which shows Lincoln holding a copy of the Emancipation Proclamation as an African American man in a loincloth kneels at his feet — is demeaning in its depiction of African Americans and suggests that they were not active contributors to the cause of their own freedom.

The drive to remove the statue comes amid a wave of calls to take down monuments to figures ranging from Confederate Gen. Robert E. Lee to President Theodore Roosevelt. The furor over the Lincoln statue represents a new front in that campaign, as demonstrators who decry racism set their sights on a monument to a president who is principally remembered for ending African American slavery.

But the current push to take down the statue is also an extension of a long and complicated history that in some ways mirrors the mixed legacy of Lincoln, who led the fight to end Southern states’ tradition of human bondage but also defended the racist views held by many whites of his era.

More than 25,000 people attended the statue’s dedication on April 14, 1876, the 11th anniversary of Lincoln’s assassination, including President Ulysses S. Grant. Abolitionist Frederick Douglass delivered the keynote address to the crowd, which included many black Washingtonians. In that famous speech, Douglass captured the contradictions that defined Lincoln’s work on behalf of black Americans.

“He was preeminently the white man’s president, entirely devoted to the welfare of white men,” Douglass said, while adding that for African Americans “the hour and the man of our redemption had somehow met in the person of Abraham Lincoln” and “under his wise and beneficent rule we saw ourselves gradually lifted from the depths of slavery to the heights of liberty and manhood.”

The memorial has had detractors ever since it was put in place.

The statue was commissioned and paid for by African Americans, including many former Union soldiers and those who had been enslaved, but its design was overseen by an all-white committee. Critics say the image of a paternalistic Lincoln and subservient enslaved man discounts African Americans’ role in winning their freedom. The model for the kneeling figure was Archer Alexander, a formerly enslaved man who assisted Union troops and escaped on his own.

Del. Eleanor Holmes Norton (D), the District’s nonvoting representative in Congress, said this week that it should be placed in a museum.

“Although formerly enslaved Americans paid for this statue to be built in 1876, the design and sculpting process was done without their input, and it shows,” Norton said in a statement. “The statue fails to note in any way how enslaved African Americans pushed for their own emancipation.”

But some scholars are urging caution as such demands intensify.

The statue, they say, is hugely important in African American history. For many years it was the only statue commissioned and paid for by African Americans and was the only statue dedicated to the promise of the Emancipation Proclamation.

“Even though the image is problematic, it’s part of our history that African Americans themselves paid for this monument and it was their way of saying slavery had ended,” said Evelyn Brooks Higginbotham, chairwoman of the history department at Harvard University and a prominent African American historian.

“The detractors are right: The image it is setting forth is the image of Lincoln bestowing freedom on African Americans without capturing the sensibility that black men were fighting in that war,” Higginbotham said. However, she added, “For a man of his time, the job Lincoln got done was astounding, and so African Americans had positive feelings about him and most still do.”

Early Thursday afternoon, construction workers in orange vests arrived at Lincoln Park and began encircling the Emancipation Memorial with tall metal fencing, reinforced by white concrete barriers.

After that, they placed similar protections around a nearby monument to Mary McLeod ­Bethune, a prominent African American educator, stateswoman and civil rights activist.

Bethune’s memorial was the first statue built on public land in the nation’s capital that commemorated an African-American woman. Angie White, a black Virginia resident who had come to see the Emancipation Memorial before it could be removed, broke off her conversation with another onlooker as she noticed the new precautions for the Bethune statue.

“Oh, gosh,” White said. “I guess they think they’ve got to protect her, too.”

A half-dozen U.S. Park Police stood guard around the Lincoln monument. At a corner of the park, a set of D.C. police officers also stood watch. Three police cars blocked vehicles’ access to North Carolina Avenue.

Elsewhere in the city, modest groups of demonstrators roamed the street, chanting against police brutality. Dozens of protesters marched from Dupont Circle to Capitol Hill, stopping along the way to hold a brief rally at the White House and to castigate a Whole Foods.

“We’re now past the stage of sexy activism,” Aalayah Eastmond, a 19-year-old survivor of the 2018 school shooting in Parkland, Fla., told a group near the White House. “This is where the real change happens, with the people that are still out here fighting.”

At Lincoln Park, however, the kind of agitated demonstration that has led to the toppling or vandalizing of other statues had not materialized shortly after nightfall. Instead, a fractious group of about 100 people milled about the park, some arguing with one another about what the monument meant.

White men and women who identified themselves as conservatives held up cameras to live-stream their exchanges with black protesters in Black Lives Matter shirts. Capitol Hill residents stood or sat in silence beneath the trees, watching. Some clutched coffee mugs.

“I grew up in this neighborhood,” said Steve Langley, 61, an African American artist and writer who still lives in his childhood home a few blocks away. “It was a symbol of white supremacy then, and it’s a symbol of white supremacy now. And it needs to go.”

Another woman, who is also African American and lives nearby, disagreed.

“It’s about humanism,” said the woman, who declined to give her name. “Not racism. Humanism.”

The two argued for five minutes.

“We are going to have to agree to disagree,” Langley said. “We could have this debate all night long. You’re not going to change my mind, and I’m not going to change yours.”

Ronald Denson Jr. shook his head in disgust when he arrived at the park close to 9 p.m. The 36-year-old D.C. resident had hoped to find a large and well-organized group ready to topple the statue.

“This is not a clown show!” Denson, who is black, yelled at the crowd of spectators.

He called the Emancipation Memorial a national embarrassment.

“It’s demeaning, hurtful and disgusting,” he said. “I would hate it, if it were a statue of me up there kneeling below that man.”

The crowd cheered as he concluded his address, then drifted back into arguments.

Denson stared at them. He looked at the statue one more time. Then he turned and headed home.

The following night, protesters planned to gather again.

Jessica Contrera, Marissa J. Lang, Julie Zauzmer, Samantha Schmidt and Perry Stein contributed to this report.