Progressives endlessly caricature free-market policies as "trickle-down" economics—giveaways to the undeserving rich with few benefits reaching the poor. In truth, trickle-down best characterizes the economic development policies pursued in deep-blue states like Maryland, where taxpayer dollars flow to the politically connected amid grandiose claims of "stimulative" effects.

A small but telling example is in Towson, a thriving suburb of Baltimore, where the proprietors of a sports-themed chain restaurant...