When Bernie Sanders ran for president, he promised to fight for free public college, universal health insurance and a $15 minimum wage. He drew huge crowds, but many Democrats declared his proposals impractical and naïve. “We are not Denmark,” Hillary Clinton tartly observed, even as she tweaked her platform to acknowledge the popularity of these ideas. A few years later , these supposedly pie-in-the-sky proposals are wildly popular among Democrats and have entered the political mainstream as important topics of discussion.

Free public college, health care for all, a living wage: These are all important causes that will improve life for millions. But there’s another proposal that belongs on the progressive to-do list: universal affordable high-quality child care. In fact, I would put it ahead of free public college: It would help more people and do more to change society for the better. Only about a third of Americans age 25 and older have a bachelor’s degree or higher, after all (although more would surely try if they could afford it). But by the time American women are 40 to 44, 86 percent of them are mothers, and unless they are affluent — or have a retired but still energetic grandma who’s willing to pitch in full time when the kids are little — the child care crisis hits families hard.

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How hard? As any parent can tell you, child care is one of the biggest costs a family faces. According to the Economic Policy Institute’s state-by-state tables, in Alabama it’s $5,637 a year for an infant and an only slightly less daunting $4,871 for a 4-year-old. That’s 69 percent of the average rent and 33.7 percent less than the cost of in-state tuition at a four-year college. At the other end of the alphabet, West Virginia parents are worse off: For them, infant care, at $7,926, is 32 percent more than the cost of college. Pick a state at random and the results are no better. New York: $14,144, or double the cost of a year of college . Illinois: $12,964. California: $11,817. No wonder child care is affordable for only a small minority of families, meaning they pay 10 percent or less of their income for it: 17.8 percent of families in Minnesota, 18.7 percent in Massachusetts, 37.7 percent in Georgia. And that’s for just one child. Most families have more.