In the same-sex marriage cases both sides have enlisted foreign law in support of their position. A group of scholars led by Harold Koh argues that the recent embrace of same-sex marriage in the law of other Western nations supports finding a right to same-sex marriage in our own Constitution. Another group of scholars, led by Lynn Wardle, observes that many more nations, including in some cases their judiciaries, have declined to interpret their guarantees of equality to mandate same-sex marriage.
Originalists must generally reject the evidence of contemporary foreign law in constitutional interpretation. Such laws should not be used as authority or indeed given any weight in decision making not because they are foreign or international, but because they are contemporary and in the ordinary case shed no light on the original understanding of the Constitution.