Liberal judges are always citing European case law. Our own Supreme Court justices have done it.
Liberals cite only foreign LIBERAL law, a point made by Justice Scalia in his debate with Breyer. The Liberals adore the UN, or foreign law, not because either has any authority, but only to the extent it reinforces their own left wing political views. For example, in a death penalty case, the Liberal justices would never mention the law of foreign countries that allow for the death penalty, but only those countries, dubbed "enlightened", whose laws agree with them.