Responding to my post this morning about gasoline prices, several people have asked why I didn't say anything about the weakness of the dollar as a possible culprit. Answer: because the dollar isn't especially weak right now, and in any case, the value of the dollar has only a slight effect on the global price of oil. Obviously a weak dollar makes all imports more expensive, so it does play a role in domestic prices, but as you can see from the chart below — where the dollar value is inverted and rescaled to show the relationship more clearly — the strength of the dollar has very little relationship to the price of oil. In 2007-08, the price of oil spiked from $60 to $140 while the dollar weakened only slightly. The recent spike began in November, while the dollar was strengthening. After that the dollar weakened a bit, then strengthened last month. It's just not a big factor here.