Sen. Elizabeth Warren is joining striking teachers on Tuesday in Chicago, where they have been marching daily since last week after hitting a negotiation impasse with city officials on their contract.

The teachers aren’t just marching for a pay raise, as Vox’s Alexia Fernandez Campbell recently wrote. Teachers want the city to put a large investment into its public schools, which are highly segregated and have growing class sizes. City officials are already offering Chicago teachers a raise, but the strikers want commitments to hire more staff and reduce class sizes written into their contract.

Warren, a frontrunner for the 2020 Democratic nomination, used to be a public school teacher. And she just released a plan to take what Chicago teachers are fighting for and replicate it around the country. Six months after releasing a plan to cancel student debt and make public college free, Warren released her K-12 education plan on Monday.

“Everyone in America should support you in this strike and the reason is because when you go out and fight, you don’t just fight for yourselves, you fight for the children of this city and the children of this country,” she told striking teachers as she joined them on the picket line Tuesday.

Warren’s new plan backs traditional public schools and teachers — not charter schools, which have attracted support but also become controversial within the Democratic Party. The centerpiece of her plan is quadrupling federal Title I funding going to public schools — an additional $450 billion over 10 years — plus increasing funding for school infrastructure and free breakfast and lunch for students. This money would come from her proposed wealth tax, which would also fund the rest of her education plans.

In addition to her plans on K-12 and higher education, Warren also released a plan for universal childcare back in February.

Her K-12 plan also commits to desegregating schools and takes a strict stance on charter schools, which are independently operated but publicly funded. Warren commits to end federal funding for the expansion of charter schools, ban for-profit charter schools entirely, and make sure charters are held to the same level of transparency as public schools.

“Seeing public education as the foundation of public cohesion in this country is a good message to send right now, we should want to strengthen it and pay into it,” said Elena Silva, the director of PreK-12 education policy at the think tank New America.

But Silva cautioned that Warren is clearly picking a side with the release of this plan and said wading into the fight around charters versus public education could potentially be thorny.

“On charters, she’s made a firm choice,” Silva said. “That’s going to get caught up in the choice debate. Rather than ending them, we can learn from their initial purpose.”

What’s in Warren’s K-12 education plan, briefly explained

The crux of Warren’s new plan is a commitment to expand federal funding of public K-12 education. But the plan also recognizes that the federal government ultimately controls a very small portion of the overall funding going to schools; 90 percent of K-12 education funding is generated by state and local revenue, leaving the remaining 10 percent up to the federal government.

Warren is trying to turn the federal money into a carrot to get states to invest more of their own money; states that adopt progressive funding formulas and keep their promises for allocating money consistently would get the additional Title I money. Her plan also calls for more transparency around the funding to better understand which education investments work and which don’t.

“This would ensure that both the federal government and state governments do their part to progressively and equitably fund public schools while still ensuring that no child gets less per-student funding than they do today,” Warren said in a Medium post announcing the plan.

Funding is a big component of Warren’s plan but it’s far from the entire thing. Here are some of the main planks of Warren’s plan, briefly explained:

Making sure there’s adequate funding for public schools: In addition to boosting the federal Title I funding for schools, Warren commits to fully upholding the federal government’s pledge to cover 40 percent of the costs of the Individuals with Disabilities Education Act that promises a free public education to those with disabilities (currently, the federal government covers less than half of that). She also plans to spend $50 billion to upgrade aging school infrastructure around the US and pledges to fully fund Bureau of Indian Education schools, which are vastly underfunded.

In addition to boosting the federal Title I funding for schools, Warren commits to fully upholding the federal government’s pledge to cover 40 percent of the costs of the Individuals with Disabilities Education Act that promises a free public education to those with disabilities (currently, the federal government covers less than half of that). She also plans to spend $50 billion to upgrade aging school infrastructure around the US and pledges to fully fund Bureau of Indian Education schools, which are vastly underfunded. Fight the increase in school segregation: Warren calls for a combination of federal funding to incentivize schools to integrate and greater enforcement of federal regulations prohibiting discrimination. Specifically, she plans to strengthen Title VI of the Civil Rights Act of 1964, giving students and parents more room to challenge systemic discrimination and segregation, and scrutinize attempts to create “breakaway” school districts that can act as a form of segregation between white, wealthier students and the more diverse districts they’re trying to leave. Warren also plans to bring back regulations rescinded by Trump’s Secretary of Education Betsy DeVos and empower the Department of Education’s Office for Civil Rights to investigate discrimination complaints.

Warren calls for a combination of federal funding to incentivize schools to integrate and greater enforcement of federal regulations prohibiting discrimination. Specifically, she plans to strengthen Title VI of the Civil Rights Act of 1964, giving students and parents more room to challenge systemic discrimination and segregation, and scrutinize attempts to create “breakaway” school districts that can act as a form of segregation between white, wealthier students and the more diverse districts they’re trying to leave. Warren also plans to bring back regulations rescinded by Trump’s Secretary of Education Betsy DeVos and empower the Department of Education’s Office for Civil Rights to investigate discrimination complaints. School safety, nutrition, and testing: Warren’s plan calls for the cancellation of all existing student lunch debt and increasing federal funding for free school breakfast and lunch for all students. On the issue of school safety, she calls for an increase in mental health providers in schools and for police officers to be trained on discrimination and de-escalation tactics. Warren’s plan says she wants to move away from an intense focus on standardized testing in K-12 settings; it calls for an end to using standardized testing as a “primary or significant factor” to close a school or fire a teacher.

Warren’s plan sides firmly with public schools and teachers — and unions are lauding her for it

As a former public school teacher, Warren devotes an entire section of her K-12 plan to talking about increasing teacher pay and decreasing the student debt for teachers. If elected, Warren has promised to name a former public school teacher to the post of Secretary of Education.

Again, states and municipalities largely get to decide how much to pay their public school teachers. But Warren’s plan to vastly increase Title I funding also comes with incentives for states to change their funding formulas to pay teachers more and make sure chronically underpaid staff like paraprofessionals receive a living wage.

It’s also extremely pro teachers union; Warren’s larger labor plan includes a pledge to work with Congress to pass an anti Right to Work bill called the Public Service Freedom to Negotiate Act, allowing public employees including teachers to collectively bargain and form a union in each state.

It’s already winning her praise from national teachers unions, which are a powerful force within Democratic politics.

“Warren’s plan is rooted in respect for our nation’s educators, and recognizes that those who know the names of the kids in their classrooms should be making education decisions,” National Education Association President Lily Eskelsen García said in a statement.

And Randi Weingarten, president for the American Federation of Teachers, called Warren’s plan a “game-changer.”

“Like so many of the other candidates’ education plans we have praised, this one is bold and thorough and lays out tangible steps and resources that are critical for all students to thrive,” Weingarten said. “What distinguishes this plan is that it is obvious it’s drawn through the lens of someone who has spent time as a teacher in a classroom.”

In recent years, teachers unions have become extremely active fighting for fair wages and benefits across the country. Warren is heading to Chicago on Tuesday to march with striking teachers in that city. But in doing so, she’s also wading into a decades-long fight on school choice and teacher pay.

“They are lightning rods; they have been for the past 20-25 years in education reform,” said Silva, of New America.

Warren is being crystal clear about which side she’s on.