In the nineteenth century, anarchist terrorists (who, by the way, were proud of the title) referred to their activities as “propaganda by the deed.” Terrorism has always been designed to make more of a psychological than a physical impact. By that standard, the Times Square bomber, whoever he is, has succeeded. Granted, the SUV packed with propane was an amateurish vehicle-borne improvised explosive device. It is, thankfully, worlds away from the sort of sophisticated truck bombs that al-Qaeda in Iraq has used to create carnage in Baghdad. Yet, nevertheless, it dominates news coverage in the “Great Satan” in a way that far more costly bombings overseas do not. Whether the culprit who placed the bomb is foreign or domestic, Islamist or survivalist, or some other creed, his purpose is to spread terror. That, after all, is the very definition of terrorism. And he has succeeded. Imagine what the impact of a bomb that actually went off would be. The very hysteria we currently exhibit — or that was evident after the Christmas Day attempted airline bombing — only make it clear to terrorists what an inviting target the American homeland remains. Of course they had better be careful. Al-Qaeda surely did not reckon with the size of the American response after 9/11; Osama bin Laden reportedly expected that we would fire a few cruise missiles and leave it at that. If a future terrorist attack succeeds on such a scale, the perpetrators may well come to regret their actions. In a way, then, such low-level attacks as the one in Times Square are actually more useful to terrorists than more successful bombings: they create terror but avoid a serious backlash.