Charter schools have been under fire and an issue in teacher strikes that have roiled the nation, including a walkout in Chicago that on Monday canceled schools there for a third day. National teachers unions have not yet endorsed a 2020 candidate, though the president of the National Education Association has said charter school support won't be an issue in that union's 2020 endorsement.

“To keep our traditional public school systems strong, we must resist efforts to divert public funds out of traditional public schools,” Warren wrote in a Medium post, adding that the charter schools “strain the resources of school districts and leave students behind, primarily students of color.”

Warren said that existing charter schools should face more aggressive oversight and be held to the same accountability standards as traditional public schools.

How would the plan treat low-income students?

One of the centerpieces of Warren’s education plan is a significant expansion in federal funding for schools. Warren would quadruple Title I funding for low-income school districts, bringing the program from nearly $16 billion a year to $45 billion a year. Both Sen. Bernie Sanders (I-Vt.) and former Vice President Joe Biden have called for tripling that funding.

Warren would also increase special education funding under the Individuals with Disabilities Education Act by $20 billion a year. In addition, the plan calls for a one-time investment of at least $50 billion in school infrastructure.

What else would she do?

Beyond funding increases, Warren vowed to eliminate “high-stakes” testing, expand federal privacy laws governing the sale of student data, and pursue investigations of anti-competitive behavior by education technology companies.

How would she pay for it?

Warren’s campaign said the total $800 billion price tag of the plan over 10 years would be paid for by her “wealth tax” on people who have assets above $50 million.

What have other candidates proposed?

Among the other 2020 candidates, Sanders has said all new funding for charter schools should be frozen and a moratorium should be put in place on their expansion. He and Biden also back a ban on for-profit charter schools, which make up a minority of charter schools.

Warren’s proposal echoes ideas from Sanders and former Obama administration Housing and Urban Development Secretary Julián Castro on school lunches in calling for universal free breakfast and lunch for all students. Warren said she would also seek to cancel the existing debt owed by students and families to school cafeterias for lunches.

What do teachers unions say?

Warren is the last of the major presidential candidates to unveil a comprehensive K-12 education platform.

The heads of the nation’s two largest teachers unions praised Warren’s education plan in statements released by the campaign. Lily Eskelsen García, president of the National Education Association, said the proposal was “rooted in respect for our nation’s educators.”

Randi Weingarten, president of the American Federation of Teachers, called it a transformational plan that would enable educators to have the resources and agency and training to do the jobs they love.

“It categorically rejects the DeVos agenda to divert much-needed resources from our public schools by rejecting for-profit charters and vouchers of any form,” Weingarten added, referring to Education Secretary Betsy DeVos, an advocate of school choice.

Nicole Gaudiano contributed to this report.