That said, many of the treaties the US has signed are now in fact US law. Either they are self executing, so just by ratifying them they because US law, or the legislature actively passed laws to execute the treaties. Not all of them though. For example, we violate the international declaration of human rights constantly, but courts have found that although we ratified it, it is not self executing, so you can't sue under it in US court. Also, we have a statute called the Alien Tort Statute that says that you can sue a non-citizen that is in the US for torts they committed that violate international law.
So it's kind of like you need a hook in US law to allow you to sue in the first place, but once you have that, the actual case is often determined by applying international law.
Our laws are our laws. Why consider others.
It still amazes me if someone dislikes something the bigotry card or race card is played. There could be other reasons for not liking Shariah law.
"I can explain it to you but, I can't understand it for you"
"He who does not think himself worth saving from poverty and ignorance by his own efforts, will hardly be thought worth the efforts of anybody else." -- Frederick Douglass, Self-Made Men (1872)
Beat your chest with false patriotism (really just arrogance) all you like, but learn about the law before you make absurd criticisms about it.
As to the nonsense about Sharia law. The only way that Sharia principals can be adopted into American law is either within a contract, or within arbitration. And both of those require mutual consent from the various parties to apply. There is no way within American law for a sudden application of Sharia principals to anyone who does not agree to it. It simply doesn't work that way. Take your bigotry somewhere else.
Liberté. Égalité. Fraternité.
I really don't care whether their bigotry was created by a flat out desire to harm people that are different from them, by a desire to make themselves feel superior, or by incomprehensibly dense ignorance. Whatever their problem is, it need to be rooted out and dealt with.
Similarly, in the context of human rights law, we have the Alien Torts Act, which allows an alien to bring a civil action in US court for a violation of various treaties and the law of nations. Obviously this has the effect of causing a US court to address the principles of legal bodies outside of US law.