The U.S. Supreme Court seemed to be mulling a flexible test for foreign patent damages Monday, with the categorical presumption against extraterritoriality taking a back seat.

Justice Stephen Breyer warned that allowing damages for infringement that occurs outside the country could lead to “chaos.” But he and a few other justices suggested the problem could be overcome by applying traditional tort causation rules.

“The problem is one of proximate cause and knowing where to cut it off. And take comity into account when you apply proximate cause. Don't have an absolute rule,” Breyer said, according to a transcript of Monday's arguments in WesternGeco v. Ion Geophysical.