The arrest of Daniel Patrick Boyd in Willow Spring, North Carolina, raises questions about when and on what grounds people should be arrested for planning terrorist attacks. According to The New York Times, he was charged with “stockpiling automatic weapons and traveling abroad numerous times to participate in jihadist movements.” The second part is horrific, and the first part seems, well, normal, at least in the parts of Kentucky and Illinois that I have visited over the past several months. In those places, quite a few Iraq veterans have stockpiled automatic weapons in their houses and apartments -- enough for World War III, in some cases, and nobody seems too bothered about it.

The veterans I know are clearly not planning a terrorist attack. And apparently the government officials had enough evidence to charge Boyd and others, all of which may lead to a series of convictions. Yet the question remains: When should suspects be arrested?

British law-enforcement officials seem more inclined to watch and wait. In other words, they will do everything they can to make sure that the suspects do not get too close to carrying out their plans but nevertheless will spend a relatively long period of time observing them. And when they do bring the suspects in, they will have a large store of evidence, including, for example, videotaped messages designed to be aired after a suicide attack has been carried out. This kind of evidence is crucial in court and is part of “operational art,” or developing an understanding of one’s enemy, as a Massachusetts law-enforcement officer (and former Marine) describes on Rethinking Security.

Americans seem more inclined to arrest suspects relatively early, a decision that can lead to botched cases. Investigators had been watching Boyd, who, by the way, had a "Support Our Troops" bumper sticker on his truck, for three years, according to The Washington Post. They decided to bring him in because they had heard that he was planning to move to Jordan. Over time, a more complete picture of Boyd, as well as of the investigation, will emerge.

--Tara McKelvey