What did the government of ancient china do to enforce their monopoly on silk?

There was a ban on Silk Worm exportation

Explanation:

It seems that silk only left China because of the the heir of a princess who was promised to a certain prince of Khotan. This most likely happened around the early 1st century AD. The princess, who refused to go to such a place without the silk that she loved so much decided to finally break the imperial ban on the silk-worm exportation.

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explanation:

anything that has been broth up to the supreme court is something of grate political divide   so just look as court cases

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.