If President Obama wants to continue blocking construction of the Keystone XL pipeline, he’ll have to come up with a new justification, because the Nebraska governor has approved a new route for the project.

“I am writing today to inform you that the State of Nebraska has completed its evaluation of a process of a proposed reroute of TransCanada’s Keystone XL Pipeline project through the State of Nebraska,” Gov. Dave Heineman, R-Neb., wrote to Obama and Secretary of State Hillary Clinton today. “I hereby, in accordance with [Nebraska law], approve the route reviewed in the Final Evaluation Report . . . I appreciate your attention to this matter.

Obama’s team pointed to Heineman when he put the kibosh on the pipeline last year. “Because of concerns expressed by numerous stakeholders, including the Republican governor of Nebraska, it was decided that an alternate route through Nebraska was necessary,” White House Press Secretary Jay Carney said on January 18, 2012. “The choosing of that alternate route has not even been completed yet.”

The president’s environmentalist base, anticipating that Keystone would return as a second-term issue, said that Obama must block Keystone in order to keep yesterday’s inaugural speech pledge to fight global warming.

“Starting with rejecting the Keystone XL pipeline, the president must make fighting global warming a central priority,” said Environment America’s Margie Alt yesterday.

Ten Republican governors and one Canadian official wrote Obama asking him to approve the pipeline in a letter last week. “With the Keystone XL Pipeline, U.S. imports from Canada, a democratic friend and ally, could reach 4 million barrels a day by 2020, twice what is currently imported from the Persian Gulf,” they wrote in the letter.

“The president must now act to permit the full development of the Keystone XL pipeline, which will increase our North American energy security and serve our national interest,” Institute for Energy Research senior vice president Daniel Kush said in a statement today. “It is time for the United States to experience the economic benefits that the pipeline’s final construction will generate.”

Last year, Obama was sensitive to economic criticism in additional to the environmentalist pressure. “However many jobs might be generated by a Keystone pipeline,” Obama said at one point, “they’re going to be a lot fewer than the jobs that are created by extending the payroll tax cut and extending unemployment insurance.”