http://www.nytimes.com/2013/01/13/magazine/should-we-tax-people-for-being-annoying.html?partner=rss&emc=rss&_r=2& " Economics offers no objective criteria for deciding what to tax or by how much. That’s one reason many libertarians, like Russ Roberts, a George Mason University economist, will never join the Pigou Club. Sure, he says, externalities exist, but that doesn’t mean the government needs to tax them. Yet in the past few weeks, there has been intense discussion among some economists about one particular externality: the social cost of gun ownership. A National Bureau of Economic Research study by Philip Cook and Jens Ludwig determined that guns cost society, on average, a minimum of $100 each and as much as $1,800. Some economists say that a Pigovian tax on weapons, rather than strict regulation, could break the political impasse on gun control. "