As expected, Conservative Canadian Prime Minister Stephen Harper has nixed a Liberal proposal to reduce penalties for marijuana possession. The legislation, which had been kicked around for three years, would have made possession of less than 15 grams (half an ounce) a noncriminal offense punishable by a modest fine. The most revealing thing about the episode was the over-the-top reaction from the U.S. government, which threatened to retaliate against Canadian decriminalization by holding up tourists and exports at the border, even though a dozen U.S. states have essentially the same policy. In a leap of logic that still puzzles me, American drug warriors argued that treating possession of personal-use quantities less harshly would boost the wholesale flow of Canadian cannabis into the U.S. It seems likely their real worry was that Canada's relatively enlightened brand of drug policy would start to leak across the border.