On January 6, 2016, TransCanada filed suit [3] in U.S. federal court in Texas, alleging that President Barack Obama's refusal to approve the pipeline project Keystone XL violates provisions of the North American Free Trade Agreement and the U.S. Constitution. According to a news report [4], the pipeline was intended to connect Canadian oil sands with American refineries, but was heavily criticized by environmental groups arguing that oils sands are a particularly polluting energy source. Obama explained his decision by noting that an approval of the pipeline would undermine U.S. leadership in the fight against climate change. TransCanada rejected this reasoning, asserting that the president had acted “without statutory authority and contrary to the expressed will of Congress to resolve an issue of domestic and international commerce that the Constitution authorizes Congress to address.”