Recent spikes in gas prices — the latest in a string of increases that have driven retail prices to record highs this year — have brought out the usual suspects who call for President Obama to release more oil from the Strategic Petroleum Reserve (SPR), the largest emergency stockpile of government-owned crude oil in the world. Last year, when President Obama released 30 million barrels from SPR, it marked only the third time that an American president has tapped the reserve to counter the threat of oil supply disruptions to the U.S. economy.