The nation’s public school curriculum may be in for a Texas-sized overhaul, if the Lone Star state’s influential recommendations for changes to social studies, economics and history textbooks are fully ratified later this spring. Last Friday, in a 10-to-5 vote split right down party lines, the Texas State Board of Education approved some controversial right-leaning alterations to what most students in the state—and by extension, in much of the rest of the country—will be studying as received historical and social-scientific wisdom. After a public comment period, the board will vote on final recommendations in May. Don McElroy, who leads the...