On March 31, U.S. District Court Judge Sue Robinson enjoined a Delaware campaign finance law passed in 2012. Delaware Strong Families v Biden, 1:13cv-1746. The law requires groups that spend at least $500 to comment on candidates for state office, to disclose the names of everyone who contributes at least $100 to that group.
If the law only concerned commentary that urges voters to vote for or against candidates, it probably would have not have been enjoined. But the Delaware law even applies to groups that publish neutral commentary or information about candidates. In this particular case, the group just wanted to publish a voter guide.