Nebraska regulators on Monday allowed the Keystone XL oil pipeline to  clear its final major hurdle, granting a victory to President Trump and  Republicans who have for years pressed for the project. But the pipeline company will not be allowed to build along its preferred route, the regulators announced, opening up new questions about how the project will proceed.

About 5,000 barrels of oil, or about 210,000 gallons, gushed out of the Keystone Pipeline on Thursday in South Dakota, blackening a grassy field in the remote northeast part of the state and sending cleanup crews and  emergency workers scrambling to the site. “This is not a little spill from any perspective,” said Kim McIntosh, an environmental scientist with the South Dakota Department of Environment and Natural Resources.