In an attempt to shift public discussion from the Obamacare train wreck, President Barack Obama is again promoting universal tax-paid daycare for preschoolers. But spending $75 billion on free preschool for all won’t work any better than the numerous times it’s been tried before.

Progressives don’t call it spending but instead use the code word “investments” to disguise tax increases. Obama wants to line up big-business support with a fairy tale that daycare “investments” will pay off by turning out kids who will be better trained to work in the future.

Lobbyists for early childhood education always cite the Perry Preschool Project, conducted years ago in Ypsilanti, Mich., as their model. But it was based on separate classes of six preschool-age children, each taught by a well-trained teacher with a bachelor’s degree in early childhood education and extra training in a special curriculum.

Teachers conducted a two-and-a-half-hour daily class, after which they had a 90-minute visit to each child’s home in the afternoon. The mothers in the Perry Project were required to be stay-at-home, married and supported by the husband’s income.

Obama’s top economist, Austan Goolsbee, argues that expenditures for universal pre-K education will produce social goodies by citing the Perry Preschool Project. But Perry’s results have never been replicated, despite many subsequent attempts, so the study is not scientifically credible.

Two embarrassing facts shoot more holes in any pretense of using the Perry Project as a model for pre-K spending. The Perry Project took place 50 years ago (1962-67) when family and child care culture was significantly different from how it is now, and, not to mention, the 123 kids chosen for the project had stay-at-home moms.

That lifestyle for children was very different from today’s: We had the nuclear family as the norm, and a different model for child care. The Perry Project did not involve a takeover of little kids by government nanny care but a mere 2.5 hours a day of training with a well-educated teacher, plus home visits to give stay-at-home mothers specialized and personal counseling.

Goolsbee cited the work of another economist James Heckman, who asserted that “each dollar invested (in government daycare) returns in present value terms 7 to 10 dollars back to society.” Heckman’s rash conclusion is endlessly echoed by so-called daycare experts, who claim the Perry Project gave society a return of six to seven times its cost. Goolsbee then solemnly pontificated that this exceeded “the historical returns of the stock market.”

With its virtually one-on-one, hands-on care of children, the Perry Project was prohibitively costly — about $19,000 a year per student in today’s dollars. The other project touted by the advocates of big government raising our children from an early age, the famous Head Start program, which began during former President Lyndon Johnson’s War on Poverty, has been in place for nearly 50 years and still has yet to provide evidence that government would do a better job than mothers.

Our generous U.S. taxpayers have poured billions of dollars into Head Start, which claims to apply the logic of the Perry Preschool Project. The government’s own evaluation of Head Start by the Department of Health and Human Services showed that, while the program had some initial positive impacts, “by the end of third grade, there were very few impacts found in any of the four domains of cognitive, social-emotional, health and parenting practices.”

Of course, we want to raise the low rankings of American kids on international tests. But the trouble is that we’ve already spent large chunks of money with minimal results. Well-established pre-K programs in Georgia and Oklahoma show that a majority of 4-year-olds failed to justify the money spent.

Just last month, the liberal Brookings Institution admitted that the supposed benefits of pre-K programs often “don’t last even until the end of kindergarten.”

We should get the facts, learn from past failures and abandon pie-in-the-sky projects before we “invest” any more taxpayer money. How about a study to find out if kids do better in school if they have the good fortune to live with their own mothers and fathers like the kids in the famous Perry Project?