This week, President Barack Obama is taking the fight to "oil speculators" and "market manipulation," demanding that traders put up more money for transactions and government ratchet up enforcement and monitoring. "None of these will bring gas prices down overnight," Obama helpfully explained in his news conference. "But they will prevent market manipulation and help protect consumers." No, they won't. They'd probably hurt consumers, and they would doubtlessly raise the cost of doing business. So for a few hundred words, writes David Harsanyi, let's treat populist agitation as if it were earnest policy.