The U.S. has become the world’s top exporter of liquefied natural gas. President Biden is finding that this superpower status comes with its own set of headaches. In the past two years, hundreds of cargoes loaded with supercooled gas departed the U.S. Gulf Coast as foreign buyers turned to America for energy supplies. Developers of export terminals have seized the momentum to advance plans to build new plants and crank out even more LNG. Now, climate activists and Democratic lawmakers are exhorting the Biden administration to halt this expansion. They argue that the federal government, which has to approve LNG...