For a few years during the middle of the 19th Century, a secretive political party rose to prominence in American politics, spurred by a cultural fear of new immigrants from Europe. Membership in the party was tightly limited, and when members were questioned about the party’s activity, they were only to respond: “I know nothing.” Today, more than a century and a half later, we have an adherent of this “know nothing” political philosophy in the White House. President Barack Obama’s standard response to questions about key problems facing his Administration is, “I know nothing.” Obama’s plea of ignorance has...