By The Editors Mitch Daniels, whom some Republicans would like to see president of something more than Purdue University, is under attack because as governor of Indiana he objected to the use of Howard Zinn’s A People’s History of the United States in public-school curricula. In recently published e-mails, the plainspoken Governor Daniels described Zinn’s work as “anti-American” and “crap,” which, when expressed in sufficiently polite language, is the professional consensus: “a polemicist, not a historian,” says Arthur Schlesinger; his work a “deranged” “fairy tale,” says Harvard’s Oscar Handlin; a man who traded in “every left-wing cliché with which the...