Ordre Public is a civil law concept according to which courts refuse to enforce the judgments of the courts of foreign countries because the judgments violate the enforcing state's core notions of public morals and public order. The concept is most often used in private international law. In some sense, it is a misnomer to talk about ordre public in American law as the terms is little used by American commentators or in American cases. Rather, the term that captures ordre public in the American context is "the public policy exception." While there may be subtle differences, for the most part Americans today, if they use the term ordre public at all, use it as interchangeable with the the public policy exception. That will be the meaning used in this article.
Marshall J. Breger, Ordre Public and the First Amendment, 13 REV. FAITH & INT’L AFF. 39 (2015).