Associated Press: In a reversal, Barack Obama is proposing the government sell 70 million barrels of oil from its strategic petroleum stockpiles. The Democratic presidential candidate says that move could help in the short-run to drive down gasoline prices that now top $4 a gallon. The proposal came in a major energy speech Obama has delivered Monday in Lansing, Mich. Previously, Obama opposed tapping into the reserves, located in caverns in Texas and Louisiana. The Illinois Democrat says …