Beheadings. Dismemberings. The world is turning into a horror movie.

The Islamic State immediately comes to mind. Terrorism is nothing new, but the Islamic State has amplified terrorism's emotional impact — perpetrating, boasting of and broadcasting atrocities ranging from the mass slaughter of innocents to staged, scripted beheadings.

It knows what it's doing. The revulsion it causes does the group no harm, and the admiration it inspires drives would-be fighters to its side from all over the world. Many of these raw recruits, eager for training and a mission, are citizens of countries the terrorists hate even more fiercely than ordinary decent people hate beheadings and dismemberings. With a British passport a terrorist can infiltrate Britain; with an American one, America; with a Japanese one, Japan.