Sen. Elizabeth Warren (D-Mass.) will unveil a major new initiative on Tuesday designed to make sure every family can afford high-quality child care , according to several people who have heard about the proposal or seen material describing it in the past week.

The plan seeks to make access to child care universal, the sources told HuffPost, by offering federal funds to providers that offer care at their facilities on a sliding income scale.

No family would have to spend more than 7 percent of its household income on child care, no matter the number of kids. Families with incomes below twice the poverty line , which is roughly $50,000 a year for a family of four, would pay nothing.

Only providers that meet federal safety, staffing and curriculum standards could qualify for the funding.

Officials with Warrens 2020 presidential campaign declined to comment on the proposal and the sources familiar with the plan cautioned that some details were still in flux as of last week.

But, the sources said, the campaign has an internal analysis that shows the initiative will likely require approximately $700 billion in new federal spending over 10 years. That is a net figure, taking into account higher economic benefits of early childhood investments, such as making it easier for new parents to return to work.

If that estimate is indicative, the new outlays in Warrens plan would be at least four times what the federal government currently spends on its main early childhood programs , which include Head Start, a block grant for state-level child care programs, and a tax credit that mostly benefits middle-class families.

To offset the cost of the initiative, the sources said, Warren will propose using revenue from her proposal for a new tax on wealth .

A Focus On Affordability And Quality

The goal of capping costs at 7 percent of income doesnt come out of thin air: Thats the figure the Department of Health and Human Services uses to officially define affordable child care. But these days, care costs a lot more than that for large numbers of families across the country.

As of 2017, married couples paid an average of 11 percent of their household income on child care, while single parents paid 37 percent, according to the research and advocacy organization Child Care Aware of America . And that figure masked enormous variation, depending on the community and type of care.

In Mississippi, for example, care for one infant at an accredited center costs about $5,300 a year, which works out to about 7 percent of median income for a married couple there. But in California, that care costs an average of $16,000 a year, which is 18.6 percent of the median income for married couples.

And the figures are dramatically higher for single-parent families, because their incomes are so much lower.

Helping families pay for child care isnt Warrens only goal. She also wants to do something about the inconsistent and frequently low quality of care options available.

In the new proposal, the sources said, Warren will call for requiring child care providers that receive federal funds meet standards similar to those that now apply to the Head Start program or the U.S. militarys child care system , which early childhood experts have long praised . Those standards include things like more rigorous training requirements for caregivers and more frequent safety inspections.

The initiative would also require qualifying child care centers to pay caregivers salaries that are competitive with what public school teachers in their communities make. That would be a dramatic shift, given the notoriously low wages child care workers currently make.

Last year, researchers at the Center for the Study of Child Care Employment found that more than half of child care workers had, over a two-year period, relied on at least one federal assistance program for low-income people. Boosting their pay is part of Warrens effort to boost child care quality , because it would allow providers to attract and retain more qualified workers.

Of course, that also makes the whole initiative more expensive.

Putting Child Care On The Political Agenda

Child care has rarely gotten serious attention in American politics. One of the exceptions was during World War II , when the federal government had to arrange for and finance care of children whose mothers were working in factories .

Subsequent research found that the initiative, known as the Lanham Act, had beneficial effects that lasted for many years. Kids who were in the program were less likely to drop out of high school, for example. But lawmakers let the measure lapse after the war ended.

In the early 1970s, as traditional gender roles started to break down and more women moved into the workplace, Congress took up child care again and actually passed major legislation that looked quite a bit like what Warren is proposing now. Then-President Richard Nixon, following the advice of conservative advisers, vetoed the legislation and said it was anti-family.

The issue mostly disappeared from the political agenda after that, until a few years ago when President Barack Obama s administration issued a series of high-profile reports on work-family and early childhood issues , and started including major child care proposals in his annual budgets.

In the 2016 Democratic presidential campaign, both Bernie Sanders and Hillary Clinton called for major new child care initiatives and Clinton, who had a long history of advocacy on the issue, indicated that she intended to give it high priority if elected. But these proposals got little media attention and there were no signs they got the attention of voters, either.

In 2017, Sen. Patty Murray (D-Wash.) and Rep. Bobby Scott (D-Va.) put together a major new bill called the Child Care for Working Families Act , which has similar goals to Warrens proposal but differs in the policy particulars. Murray and Scott have said they intend to introduce an updated version of their legislation this year.

But these kinds of child care initiatives are unlikely to become law anytime soon, given Republican control of the Senate and the White House and the GOPs skepticism of large-scale government spending programs. The first chance to pass major child care legislation would probably be 2021, if Democrats win the White House which means the attention Democratic candidates could determine what priority, if any, it is given in the next Congress.

The fact that somebody is coming out of the blocks and talking about it in such a big way, its a really important sign, said one person who had seen the Warren plan.

A proposal like Warrens would likely face serious political opposition, in part because of its scale. But Warren has spoken frequently about her difficulty finding child care as a working parent, suggesting she considers the issue worth trying to push as a presidential candidate.

We cycled through one child care arrangement after another and every transition sent me into a near panic every time it represented a failure, Warren said during a speech before the National Womens Law Center in 2017. A few months later, she was a key player on a bipartisan agreement to increase federal funding for early childhood programs by $2.8 billion .

Warren is by no means the only declared or prospective Democratic presidential candidate who has shown an interest in these issues.

Sen. Kirsten Gillibrand (D-N.Y.) in particular has a long record of proposing and endorsing policies that would help working parents, including proposals to reduce child care expenses , while Sen. Sherrod Brown (D-Ohio) is a longtime advocate for expanding a child-based tax credit .

Former San Antonio Mayor Julian Castro has frequently touted his signature accomplishment, the citys new pre-kindergarten program , as a model for the nation.

One source suggested that with Warrens plan on the table, other 2020 candidates are more likely to introduce major proposals of their own. Creating an arms race in child care, said one source, would be a big accomplishment.

CORRECTION: An earlier version of this article mistakenly referred to the National Womens Law Center as the National Womens Law Caucus.