Momentum is building toward providing universal pre-kindergarten for children throughout the United States.

President Obama again emphasized his support for expanding early childhood education in this year’s State of the Union address, while Mayor Bill de Blasio has announced his intention to implement universal, full-day, pre-kindergarten throughout New York City this fall. Oklahoma and Georgia have already instituted statewide programs, while here in Maine U.S. Rep. Mike Michaud has made providing “Universal Public Pre-K Programs” central to his gubernatorial campaign.

Universal pre-K is indeed an idea whose time has come — again.

America’s relationship with publicly provided preschooling is somewhat ambiguous — and long. Almost 75 years ago, for instance, during World War II, when the draft significantly reduced the number of able-bodied men necessary to keep the nation’s factories and shipyards operating at full capacity, women stepped in to resolve the “manpower” shortage. Although most were single, some were married with children and had moved to towns where defense jobs were plentiful, preventing them from relying on family networks for child care. Consequently, as the need for more women to take up war work increased, federal, state and local governments joined with defense industries in establishing centers to provide care for the young children of working mothers.

These centers were initially meant to serve a solely custodial function — a place to put the kids while Mom was at work welding and riveting. Many of the women administrators charged with establishing the centers, however, were educators with loftier goals. Declaring the centers “nursery schools” rather than day care and insisting that only college graduates trained in early childhood education be hired as teachers, wartime nursery school administrators drew on the most current research in the field of child development. Providing a high-quality educational program, the schools integrated academic enrichment with creative expression and play while maintaining a distinct focus on children’s health and nutrition. The result was the establishment and operation of nursery schools that by most accounts rivaled many of today’s best pre-K programs.

Sadly, most lawmakers conceived of wartime nursery schools solely as an emergency measure. As World War II came to a close, many Americans expected the employed mothers of young children to put down their welding irons and riveting guns and return home. Although many working mothers did not, wartime nursery school budgets were nonetheless slashed. Few of these innovative schools survived the war’s end.

It has taken far too long for us to return to the idea of universal pre-K. Nevertheless, as Maine moves toward implementing these programs, there is much we can learn from America’s wartime experiment in early childhood education.

First, we should keep in mind that preschools are indeed educational places rather than simply custodial institutions. As such, they should employ college graduates who are certified in early childhood education and well versed in both the theories and practices of child development.

Second, with the implementation of Common Core standards in kindergarten, the temptation to use universal preschool for the purpose of preparing students for the Common Core will be great. Although academic enrichment should undoubtedly be a central component of pre-K programming, we should resist the impulse to turn preschools into staging grounds for kindergarten and, instead, ensure that creative expression and play are valued equally in pre-K classrooms.

Finally, we should take seriously the wartime nursery schools’ emphasis on children’s health and nutrition. If 75 years ago, during a period of national crisis, municipalities could find ways to employ nutritionists and health care professionals to serve the children in their care, we should be able to do no less today.

Michaud is right when he claims in his “Maine Made” economic development plan that universal public pre-K will have “an enormous impact on children’s later success in school” as well as “significant positive long-term economic and fiscal benefits, particularly for students from low-income families.”

These benefits will only accrue, however, if we are certain to make the investments necessary to provide a high-quality preschool education for all children throughout our state. It’s about time we finally did so.

Charles Dorn is an associate professor of education at Bowdoin College who specializes in the history of education.