The United States Supreme Court has begun re-examining whether oil giant Shell was complicit in acts of torture by the Nigerian government during the 1990s. The case has legal ramifications for a 200-year-old statute that allows foreign plaintiffs to file suits in American courts. In the Kiobel vs Royal Dutch Shell case, the oil company is accused of being an accomplice to torture, executions and crimes against humanity between 1992 and 1995 in the Niger Delta region. But Shell are arguing that the so-called Alien Tort Statute doesn't apply to them. So, what does this mean for the protection of human rights in US courts? RFI speaks to Katherine Gallagher, an American constitutional law expert to find out more.