A person is guilty of unlawfully solemnizing a marriage when: 1. Knowing that he is not authorized by the laws of this state to do so, he performs a marriage ceremony or presumes to solemnize a marriage; or 2. Being authorized by the laws of this state to perform marriage ceremonies and to solemnize marriages, he performs a marriage ceremony or solemnizes a marriage knowing that a legal impediment to such marriage exists. Unlawfully solemnizing a marriage is a class A misdemeanor.
New York Legal Code