As we have noted here many times, military training is generally the key that separates competent terrorists from wannabes. But whether actual or would-be jihadists, these Muslims are motivated by Islamic supremacism, the belief that sharia, Islam’s ancient, totalitarian law, must be imposed on society. Based on all this, there is abundant Washington and media speculation that the attack is “ISIS-inspired.” This is consistent with the bipartisan, government-approved inanity we have been following for a quarter-century, what I often call the political class’s concoction of “An Islam of Their Very Own.” It goes something like this: Islam is a religion...