President Obama's initial reluctance to label the bombing of the Boston Marathon an act of terror was odd; his correction of the record on Tuesday was welcome. Although no information has been released so far about any suspects, it is doubtful that this terrible attack, which killed three and maimed many more, was the work of criminals or apolitical lunatics such as the Newtown, Conn., killer Adam Lanza. Both crooks and kooks prefer to kill with firearms. Explosives, by contrast, are the signature weapon of terrorists.
It is no coincidence that the era of modern terrorism began at almost the same time that Alfred Nobel invented dynamite: 1867. There had been a few isolated terrorist gangs before then—which is to say, groups that murdered civilians in order to further a political or religious agenda. The Sicarri, the Jewish dagger-men who killed Roman collaborators in first-century Judaea, come to mind. So do the Assassins, the Shiite sect that terrorized Middle Eastern leaders in the Middle Ages. But such examples are few and far between, whereas the late 19th century saw the flowering of the first age of international terrorism, featuring such organizations as the Ku Klux Klan, the Irish Fenians, the Russian Nihilists and the anarchists who operated in both Europe and the Americas.