The Supreme Court seemed wary on Tuesday of letting prosecutors use a federal obstruction law to charge hundreds of rioters involved in the Capitol attack on Jan. 6‚ 2021. A decision rejecting the government’s interpretation of the law could not only disrupt those prosecutions but also eliminate two of the federal charges against former President Donald J. Trump in the case accusing him of plotting to subvert the 2020 election. Mr. Trump’s case did not come up at the argument‚ which was...