(Melina Mara/The Washington Post)

Hillary Clinton this week unveiled her vision for more quality child care in the United States, a lofty plan that includes raising pay for the industry’s workers. But the boldest idea targets parents, who now face day-care costs that rival college tuition. Clinton wants to cap that expense at 10 percent of a household’s income.

Considering that some people spend more on child care than rent, such a price shift would significantly ease the financial strain for families nationwide. Getting there, however, could be an extraordinary challenge.

Average child-care costs in the United States devour at least 30 percent of a minimum-wage worker’s earnings in every state, according to a report last year from the Economic Policy Institute, a Washington think tank.

To pay for a year of full-time infant care in Hawaii, for example, where the median minimum wage in 2015 was $7.75, a full-time worker would have to fork over every paycheck from January to September. Those at the bottom of the wage scale in New York and Massachusetts would have to spend about 80 percent of their annual earnings.

And in D.C., often cited as the country’s priciest child-care market, minimum-wage workers would have to part ways with slightly more than their entire income.

“These high costs severely squeeze working families, prevent too many children from getting a healthy start, and act as a disincentive for parents to stay in the workforce,” the Clinton campaign said in a statement.

Democratic contenders this election cycle have focused on the needs of working families.

Clinton’s child-care proposal follows her push for paid family leave and universal preschool. Her rival for the Democratic Party’s presidential nomination, Sen. Bernie Sanders (I-Vt.), has pledged to tax the wealthy to create a public child-care system.

Republican front-runner Donald Trump has largely avoided the subject. He has referred to child rearing in an interview about his personal life as his wife’s job. The family, he said, does not employ nannies.

Clinton intends to accomplish the 10 percent cap with tax credits and subsidized child care, according to her campaign. Details on how the plan would be funded and executed will come later this year, aides said.

A proposal last year from the Center for American Progress, a policy idea wellspring for Democrats, could offer a clue. Carmel Martin, CAP’s vice president of policy, said she has advised the Clinton campaign on child-care issues.

CAP recommended creating a new child-care tax credit, worth up to $14,000 per child. Under the plan, which would target low- and middle-income families, the tax credit would be advanced to parents on a monthly basis and paid directly to child-care provider. The centers, meanwhile, would qualify to receive federal money only if they complied with the state’s quality standards.

The market alone can’t fix affordability and quality issues in American child care, Martin said. A government investment into the system, she said, would boost the current and future labor force.

“It’s a huge economic issue for American families,” Martin said. “It’s how we ensure people can go to work and be productive, and children can be in a safe, stable environment.”

Finding a way to pay for day care remains a struggle for families across income levels. A Washington Post survey last year found more than three-quarters of mothers and half of fathers say they’ve skipped work opportunities, switched jobs or quit to watch their kids.

Over the last 30 years, weekly spending on child care for families with a working mother has nearly doubled, according to the Census Bureau. The average annual cost of infant care now exceeds the price of public college tuition in two-thirds of states.

Families on the poverty line qualify for public assistance. Obtaining that help, however, can become a lengthy trial. Just 17 percent of children eligible for child-care subsidies under federal law in 2011 received the aid, a report from the Institute for Women’s Policy Research.

Some kids are stuck on waiting lists for weeks, even months. Some parents have trouble taking off work to wait in long enrollment lines.

More on Wonkblog:

This could be the big new idea about childcare from Democrats

Do we need government-supplied daycare?

The staggering cost of daycare when you only make minimum wage