WASHINGTON (Reuters) - Democratic presidential hopeful Bernie Sanders is calling for a sweeping overhaul of publicly-funded charter schools, rolling out a plan on Saturday that will put him at odds with some of his opponents and underscore his renewed efforts to win black voters.

FILE PHOTO - U.S. 2020 Democratic presidential candidate and U.S. Senator Bernie Sanders (I-VT), speaks at the 2019 National Action Network National Convention in New York, U.S., April 5, 2019. REUTERS/Lucas Jackson

Sanders, a U.S. senator from Vermont, wants to ban for-profit charter schools and halt the creation of new charter schools while imposing new rules on the existing ones, according to a summary of his proposal provided by his campaign on Friday.

Charter schools receive government funding to operate but are more autonomous than traditional public schools. Students do not pay to attend.

Most charter schools are operated by nonprofit groups, and many take private donations on top of government funding. However, a pro-charter school group estimates 15 percent of them are operated by for-profit companies. Additionally, some nonprofit charter schools have come under fire for contracting with for-profit companies to operate the schools.

Charter schools, which enjoyed bipartisan support at their inception in the 1990s, have become the subject of increasing division. Many Democrats have grown critical of them, arguing the schools are used by the wealthy to pad their pockets while still neglecting millions of students in failing schools.

Groups like the NAACP have become vocal opponents of the current charter school system.

But charter schools remain popular in some predominately black communities, where they are seen as the best option where public schools are weak.

As a result, Sanders’ proposal, meant to show how his liberal policies could help minorities, comes with some political risks for the candidate, who struggled in his last presidential campaign in 2016 to gain support from black voters.

Sanders will roll out a comprehensive education platform in a speech in South Carolina on Saturday, his campaign said.

Supporters argue charter schools can serve as laboratories for innovation in education that can flourish without the bureaucratic constraints of traditional schools.

But critics of charter schools say they have done little to export the innovation they promised to traditional schools, which still educate the vast majority of students. Instead, critics argue, charter schools have taken resources from the rest of the public schools to serve a small, select group.

Critics also say the schools are mainly serving middle-class, predominately white populations to the detriment of students, mainly minorities, in traditional public schools.

The position taken by Sanders, one of more than 20 Democrats vying for the nomination to challenge Republican President Donald Trump in the November 2020 election, is in stark contrast with some of his opponents.

Former Congressman Beto O’Rourke of Texas has previously voiced support for charter schools, and U.S. Senator Cory Booker was a vocal supporter of them as mayor of Newark, New Jersey.

Booker’s support of charter schools is proving to be a liability with some black voters.

Booker is “well liked,” said Corey Strong, former chairman of the Shelby County Democratic Party in Memphis, Tennessee, but he “has an issue with charter schools.”