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Law of nations recognized by Constitution

Another power given Congress to define and punish offenses against the law of nations, thus giving that law express constitutional recognition. The law of nations has been defined to be the rules of conduct regulating the intercourse of States. Hence without the express constitutional recognition indicated, it would be binding on the government as one of the family of nations. It modifies the relations of independent States in peace, and sets limits to their hostilities in war. When war breaks out, the rights, duties, and obligations of parties belligerent spring from and are measured by the laws of war, a branch of the law of nations. When war exists, whatever is done in accordance with the laws of war is not regarded as arbitrary, but lawful, justifiable, and indispensable to public safety.