In the recent supreme court case Nestlé USA Inc. v. Doe, the court ruled that Nestlé USA could not be sued for actions it took overseas--specifically, it could not be held liable for knowingly aiding and abetting in the slave trade on the Ivory Coast. I find this very strange, given that participating in the slave trade is a gross violation of human rights. There was a similar ruling in Kiobel v. Royal Dutch Petroleum Co., though in that case, the actions of the corporations were even more extreme, and included extrajudicial killings. From what I can gather, a US citizen could literally commit first-degree murder in another country, and not be held liable in US courts. From looking at the decision in Kiobel v. Royal Dutch Petroleum Co., it seems a corporation could go so far as to commit genocide in another country and not be held accountable in US courts. My question is basically this: Why is US law set up in this way?
From what I can gather, a US citizen could literally commit first-degree murder in another country, and not be held liable in US courts.
From looking at the decision in Kiobel v. Royal Dutch Petroleum Co., it seems a corporation could go so far as to commit genocide in another country and not be held accountable in US courts.
Why is US law set up in this way, and why has nothing been done to change it?
The modern nation-state is part of the Westphalian tradition of sovereignty which takes as a core value that the internal laws of each nation-state are a matter for it and it alone. This is baked into international law as part of the UN charter: "nothing ... shall authorize the United Nations to intervene in matters which are essentially within the domestic jurisdiction of any state."
The basic assumption of criminal law is that it is, by default, territorial. If a US national commits a crime in the Ivory Coast, then that is primarily the Ivory Coast's problem to deal with. There are both practical and political reasons why this is a good idea.
The practical matters are that law enforcement and the courts in the Ivory Coast have the on-the-ground resources and knowledge to investigate and prosecute the crime and the US doesn't. US police forces can't collect evidence and interview witnesses in the Ivory Coast unless the Ivory Coast allows it. US courts can't subpoena witnesses.
On the flip side, foreign jurisdictions don't have to follow the US Constitution when conducting searches and beating up, I mean, interrogating, suspects. That may make a lot of the evidence collected in foreign jurisdictions inadmissible in US courts.
The political reasons are the US (and anyone else) should stay the f&^% out of the internal operations of other countries. The treaty of Westphalia ended 30 years of the most brutal warfare in history, which killed an estimated one-third of Europe's population, which was largely fought because the ruler of country X wanted to tell the ruler of country Y what religion they should have.
Extraterritorality in US law
Constitutional restrictions can limit exterritoriality. First, the statute must be within Congress' power to enact. Second, neither the statute nor its application may violate due process or any other constitutional right (see above).
The presumption is that Federal laws only apply within US territory. To be extraterritorial, Congress must make this clear, ideally explicitly, but the courts can find that some laws are implicitly extraterritorial based on their language.
Other nation's approach is different. For example, a French citizen is subject to French as well as local law everywhere in the world.