President Barack Obama's tearful intervention this week in America's gun control debate had an immediate impact. Stocks in arms makers jumped in anticipation of a fresh buying surge by fearful citizens.
Mr Obama would have known this perverse effect was likely. Last month, after the San Bernardino massacre, when an Islamist-inspired husband and wife team killed 22 people in the Californian town, gun and ammunition sales jumped. Such is the climate in gun-saturated America that school classes and workplaces routinely prepare for mass shootings in the way that New Zealand pupils practise earthquake drills.
At town hall meetings police officers deliver lessons in surviving the nightmare of having an "active shooter" in the neighbourhood.
People are encouraged to Google the layout of the local sports stadium before going to a game or concert and to check the exits of the suburban supermarket. Mass shootings occur in the United States about once a month. Studies indicate some 92 Americans die every day from gun deaths. About a third of these are homicides. A child in America shoots someone on average once a week because guns are so easy to find and fire.
No other developed country comes close to this staggering level of gun violence. Yet the nation pussyfoots around the charged issue of removing from circulation the vast arsenal of military-style weapons and refuses to renew a ban on semi-automatics sales. It is impossible to know the exact number but by some estimates Americans own 300 million guns. Clearly some end up in the hands of deranged individuals.