In this March 24, 2017, file photo, President Donald Trump, flanked by Commerce Secretary Wilbur Ross, left, and Energy Secretary Rick Perry, is seen in the Oval Office of the White House in Washington, during the announcing of the approval of a permit to build the Keystone XL pipeline, clearing the way for the $8 billion project. A federal judge in Montana has blocked construction of the $8 billion Keystone XL Pipeline to allow more time to study the project’s potential environmental impact.