The last time the U.S. dealt seriously with creating a child care system was 45 years ago, when Congress passed the 1971 Comprehensive Child Development Act to provide quality child care, including education, medical services and nutrition in locally administered centers, and use federal dollars to subsidize fees on a sliding scale.

But President Nixon forcefully vetoed the bill, arguing that responsibility for child care belongs to parents and that federal funds should not be committed to communal child care. Forty-five years later, the fundamental question Nixon raised is still at the heart of the childcare debate: who is responsible for child rearing?

The clear answer is that both parents and government have responsibilities. We have already put that philosophy into practice for older children. We send children through K-12 schooling because we think families need major assistance in providing their children with the cognitive and social skills required in a complex society, and we fully fund those systems because we think that education is a public good—that the benefits of education accrue not only to children and their parents but also to the public, especially to our economy and our democratic institutions.

We need to extend our thinking about the public benefits of education to infants and toddlers. In 1971, it was hard to convince people that there were benefits to be had from infant and toddler education, but since then, the evidence has become unequivocal. Neurological studies of the brain show decisively the importance of the experiences of infants and toddlers on the development of their cognitive abilities, and studies of Head Start and other pre-school programs point to positive benefits that exceed costs.

Many conservatives would like to return to an era when mothers did not have a paid job. But in the 45 years since Nixon’s veto, the labor force participation rate of mothers with young children has risen considerably. Today, almost two-thirds of mothers with children under the age of 6 are in the workforce, and for black mothers, the rate is slightly more than 70%.

Parents who are employed experience three difficulties with child care —availability, affordability and quality — and the market system by itself cannot remedy them.

A recent study by the Economic Policy Institute(EPI) across 10 metropolitan areas found that families paid between $67,536 and $108,313 a year (depending on their geographic location) for child care for one infant and one 4-year old, which made up between 19.6% and 31.2% of their median family income. The study also found that almost all families in more than 600 communities were spending more than the 10 % affordability level established by the Department of Health and Human Services.

Low availability and lack of affordability are two sides of the same coin. New providers do not come into the market because there are not enough customers willing to pay what child care costs, and these potential suppliers see no way to decrease their costs. Although other industries in our economy have been able to lower their costs through improvements in productivity, childcare has not and cannot. The technology for caring for young children and educating them has remained the same for decades, and about 80% of the cost of child care is labor.

Child care workers are some of the poorest paid in the country The mean hourly wage of child care workers is $9.99, less than half the wage for all workers ($23.23), and lower even than the wage for parking lot attendants ($10.83). But even with these low wages, unless parents receive a subsidy, many cannot pay what child care costs.

Quality is a more complex issue. Studies on the quality of child care are outdated at best; they’re 10 to 20 years old, and they paint a dismal picture. Although many parents are paying astronomical fees, most of it is not of high quality.

Raising the wages of child care workers is an important means of increasing quality, even though it simultaneously makes child care more expensive. Higher wages will attract more highly trained people as child care providers and lessen their turnover. Right now, child care workers have one of the highest turnover rates in the economy—about 30 percent. This high turnover makes it more problematic for children to develop secure bonds of attachment with their caretakers, and more challenging for caretakers to track their children’s social, emotional, and language development.

Quality child-care depends upon teachers — their knowledge base and their interactions with children. To deal more directly with quality, when Clinton fleshes out her child care plan, she urgently needs to include funds earmarked for community colleges to train child care workers on site. Many child care workers do not have cars to travel to community colleges; nor do they have the time.

Two of my doctoral students and I interviewed workers at a child care center in Santa Clara County, CA., where a community college had done on-site training. One of the workers poignantly related her appreciation of the training. For the first time, she said, she understood why children bite one another. And based on that understanding, she now recognized that she could lessen the incidence of biting by teaching children alternative ways to express their anger

Donald Trump has said that he thinks employers should provide child care for their workers and that it is simple to do so — just hire a few caretakers. A new child care system should definitely encourage employer-based child care because it is often of very high quality. But it is not possible for all employers to provide child care.

And to create a high-quality center requires more than just a few caretakers. For the economics to work, the employer has to be fairly large and have a considerable number of young parents or parents-to-be. Some employers purchase slots in existing child care centers as an employee benefit, and that should also be encouraged. But as we have learned from our health care experience, relying solely on employers to provide health or child care benefits to all who need them leaves too many unserved. We need a mixed system where parents can use their subsidies for care run by employers, non-profits, for-profit centers and governments.

It is not accidental that the first woman candidate for the U.S. presidency is already working toward policies to support women with children. If we can enact Clinton’s agenda, millions of families could benefit and our economy and society will be stronger.