Justice Sandra Day O’Connor on Thursday dismissed growing criticism about the Supreme Court’s use of international law in its opinions, saying it makes sense for justices to look at foreign sources when a point of law is unclear.

O’Connor, a Reagan appointee, participated in a lively one-hour discussion at the National Archives with Justices Antonin Scalia and Stephen G. Breyer. She said if there is no controlling U.S. precedent or the viewpoint of states is unsettled, “of course we look at foreign law.”