The U.S. Supreme Court on Tuesday ruled that a federal law governing the natural gas market does not shield energy companies from state antitrust claims made over the western U.S. energy crisis between 2000 and 2002. The ruling, on a 7-2 vote, was a loss for several energy companies, including American Electric Power Company Inc, Dynegy Inc and ONEOK Inc, which were accused of manipulating published price indexes that led to a spike in gas prices.