The United States is producing more oil today than it has since 1998, but gasoline prices are still high, averaging more than $3.50 per gallon nationally in early June. New technology is making it possible to extract oil from tar sands and shale rock, but that oil is expensive, and its production causes major environmental impacts. President Obama advocates expanding production of all energy sources, including oil, gas, nuclear power, wind and solar, while warning that the United States can never pump enough oil to sway world prices. Republicans counter that the Obama administration has restricted oil production and that drilling should expand in Western states, the Arctic and coastal waters. Environmentalists want more support for technologies to replace oil, such as electric cars and biofuels. But until those sources become economically competitive with oil, the United States will be subject to price swings in a world oil market that it cannot control.