Nebraska Gov. Dave Heineman this week said a plan by TransCanada to reroute the planned Keystone XL around the sensitive Sand Hills area led him to notify the White House of his consent. Heineman initially blocked the project out of environmental concerns.
"Because the pipeline has gone through the most exhaustive environmental scrutiny of any pipeline in the history of this country and you already determined that oil from Canada is in the national interest, there is no reason to deny or further delay this long-studied project," the senators' letter reads.
Pipeline opponent Bold Nebraska contends that many economic benefits touted by Keystone XL supporters are overstated. Opposition groups in Texas have staged high-profile demonstrations to express concern over so-called tar sands, a controversial type of oil designated for the pipeline.
Keystone XL needs federal approval because it would cross the U.S.-Canadian border. TransCanada is building the Gulf Coast Project, the U.S. leg of the pipeline.