 In United States v. Smith ( 1820 ) , in an opinion by Justice Story , the Court upheld a conviction under the 1819 statute , holding that Congress could leave the definition of piracy to the law of nations . After reviewing the history of foreign ( primarily English ) law , Justice Story declared : " We have , therefore , no hesitation in declaring , that piracy , by the law of nations , is robbery upon the sea , and that it is sufficiently and constitutionally defined by the fifth section of the act of 1819 . " In a rare dissent , Justice Livingston argued that Article One , Section Eight , Clause Ten obliged Congress to define piracy with more specificity . The facts in Smith were almost identical to those which Palmer had held could not be reached under the Crimes Act of 1790 : a U.S. citizen pirate , commissioned by a government in Buenos Aires , had led a mutiny , seized a new ship , and then robbed a Spanish ship . 
