If congress passes a law because of "foregoing powers," it is likely based on the article 1, section 8 of the constitution.
The Necessary and Proper Cause of the constitution provides the congress all necessary power to pass and execute laws. Even though this clause caused some controversy, it did not add extra power to congress; it just made explicit what was otherwise implicit.
It called for protection of equal privileges for all countries trading with China and for the support of Chinese territorial and administrative integrity
