Simply ban ALL foreign laws or rulings to be used in our system of courts and law. No foreign law shall be used to determine anything against anyone for anything. If it is not written into US law, it does not exist. Simple as that in my humble opinion.
That is one aspect. Another principle is all people should have equal treatment under the law. We should not have different laws applied to people based on their racial or ethnic group.
I’m pretty sure the U.S. Constitution already says that.