The renewed focus on the pipeline comes as Obama pledged during his inaugural address to respond to the threat of global warming. Environmental groups and some Democratic lawmakers argue that approving the pipeline would directly contradict that promise.
The pipeline would carry heavy oil derived from tar sands in western Canada. The heat-intensive process uses more energy than traditional oil, producing more heat-trapping gases that contribute to global warming.
Environmental groups have been pressuring Obama to reject the pipeline, citing the oil’s high “carbon footprint.” They also worry about a possible spill.
At a news conference Wednesday, senators from both parties said the Nebraska decision leaves Obama with no other choice but to approve the pipeline, which would carry up to 800,000 barrels of oil a day from tar sands in western Canada to refineries in Houston and other Texas ports. The pipeline also would travel though Montana, South Dakota, Nebraska, Kansas and Oklahoma.