Bangladesh, Sept. 7 -- America has spent decades building a welfare system that can subsidize almost everything except the one institution politicians constantly claim they want to strengthen: the family.

Now the Trump administration is preparing to challenge that contradiction.

A proposed change to the federal Child Care and Development Fund, or CCDF, would allow certain married households with a stay-at-home parent to qualify for childcare assistance. Under the proposal reported by The New York Times, a married couple could receive assistance when one parent remains home to care for the children while the other works at least 35 hours a week.

That sounds modest. It is.

Yet some voices on the right are already treating the proposal a...