The term “soccer mom”—political shorthand for the upscale suburban women President Clinton courted so successfully in the 1990s—may have fallen out of use with the Beltway set in more recent years, but this swing voting bloc is still around. Just ask Arne Duncan.

As President Obama’s education secretary and the administration’s head cheerleader for the new Common Core academic standards, Mr. Duncan has spent four years trying to convince the country that the biggest problem with K-12 schooling is insufficient federal intervention....