A federal judge has ruled that New Jersey may not enforce its new law requiring disclosure of certain “dark money” campaign contributions while a First Amendment challenge to the law proceeds.

Americans for Prosperity, the group that filed suit in June to challenge the law known as S-150, has demonstrated it has a “reasonable probability of winning on the merits at trial” on its claim that the law is unconstitutional, U.S. District Judge Brian Martinotti for the District of New Jersey said when he granted the injunction Wednesday.