LONDON — It is the duty of all public officials to "do something" whenever a new threat appears, even if there is nothing sensible to be done. If they don't make a show of solving the problem, the media will punish them severely. So we have had a vigorous U.S. government response to the recent apprehension of the Underpants Bomber.

Umar Farouk Abdulmutallab was from Nigeria, and he was Muslim. Therefore, the U.S. government has announced that all travelers to the United States from Nigeria, Pakistan, Syria, Iran, Sudan, Yemen and seven other Muslim or partly Muslim countries will face extra checks at airport security. They will be patted down by hand, and their carry-on bags will also be searched by hand. So that's all fixed, then. No more exploding underpants.

Except that Abdulmutallab's underpants were on his body, so hand searches of cabin baggage aren't going to help much. Moreover, it is far from certain that a physical pat-down of Abdulmutallab would have detected the guilty underpants.