In cases where the burden falls primarily on the poor, a temptation might be to subsidize the consumption of the externality-generating good. But this would be self-defeating-a subsidy that lowers the price of the externality-generating good underconfront the purpose of the lowers the place, which is to assure that consumers confront the full social costs of the good . In short, if the distribution implications of policies that correct externalities are viewed as undesirable, some mechanism other than price subsidies should be used to rectify the situation. Unfortunately, politicians frequently don't understand or ignore this logic. For example, the climate cap-and-trade bill that the House of Representatives approved in 2009 passed on a large share of the value of the permits to households in a way that decreased their incentives to conserve energy. (The measure was eventually defeated in the Senate.)