A long-standing lawsuit over the use of forced child labor on African cocoa farms has reached the U.S. Supreme Court, wher arguments turned on whether and how the American justice system allows such claims.

The lawsuit, against Nestlé USA and Cargill Inc., was originally brought in 2005 on behalf of six persons claiming to have been enslaved on African cocoa plantations in the 1990s. It argued that Nestlé and Cargill should be held liable for the abuse under the Alien Tort Statute, which allows non-U.S. citizens to seek redress in American courts.

The suit was dismissed twice by a federal district court in 2017 but reinstated by an appeals court in 2018. The Supreme Court is pondering whether to allow the suit to go forward.

Some of the arguments centered on whether the defendants knew, or could be expected to know, whether the cocoa they were purchasing was harvested by enslaved workers. Justice Samuel Alito pointed out that the lawsuit doesn’t specify a degree of culpability for Nestlé and Cargill.

“After 15 years, is it too much to ask that you allege specifically that the defendants ... who are before us here specifically knew that forced child labor was being used on the farms or farm cooperatives with which they did business?” Alito said, as quoted by Reuters.

But much of the questions revolved around whether the Alien Tort Statute, a law from 1789 originally drafted to deal with piracy, is applicable in this case.

Other Supreme Court decisions have whittled down the scope of the Alien Tort Statute. A lawyer for the defendants argued that the law should not be applied to corporations, but some of the liberal justices appeared to have a problem with that assertion.

“If you could bring a suit against 10 slaveholders, when those 10 slaveholders form a corporation, why can’t you bring a suit against the corporation?” Justice Elena Kagan asked, as quoted by the Wall Street Journal.

A ruling is expected by June.