Each year, some 750,000 Americans are arrested for possession of small amounts of marijuana. Is that really the optimal use of our police force?

In contrast, legalizing and taxing marijuana would bring in substantial sums that could be used to pay for schools, libraries or early childhood education. A Harvard economist, Jeffrey A. Miron, calculates that marijuana could generate $8.7 billion in tax revenue each year if legalized nationally, while legalization would also save the same sum annually in enforcement costs.

That’s a $17 billion swing in the nation’s finances — enough to send every 3- and 4-year-old in a poor family to a high-quality preschool. And that’s an investment that would improve education outcomes and reduce crime and drug use in the future — with enough left over to pay for an extensive nationwide campaign to discourage drug use.