By refusing to hear arguments over whether a state can limit campaign spending by corporations, the Supreme Court refused to reconsider its decision in Citizens United v. Federal Election Commission on Monday. In a 5-4 ruling, the court struck down a century-old Montana ban on corporate political money. By doing so, the high court held that there is no exception to Citizens United at the state and local level.

Since the Citizens United decision in 2010, a new dawn on corporate political spending has been playing out in federal election campaigns. Citizens United held that prohibiting corporations and labor unions from making independent expenditures on electioneering communications violated the First Amendment’s free-speech protections. Accordingly, Citizens United reversed decades of statutory and case law that prohibited corporations from using their general treasuries to fund “express advocacy,” which is direct political advertising against candidates for federal office. However, until Monday, the impact of the decision was only seen at the federal level.

With the high court’s decision in American Tradition Partnership Inc. v. Bullock, the Court has erased any ambiguity as to whether Citizens United applies to state and local laws. In American Tradition Partnership Inc., three corporations challenged the legality of Montana’s long-standing state prohibition that barred corporations from making political expenditures in connection with candidates in the wake of Citizens United. This prohibition was upheld by the Montana Supreme Court on the basis that it was justified by the state’s interest in preventing corporate influence in state elections. The three corporations appealed and emerged victorious with the high court’s summarily reversal of the Montana court’s ruling.

This latest Supreme Court decision illustrates that in the post-Citizens United world, campaign finance reform continues to evolve and stretch its reach. Those attempting to navigate this new realm of election law should anticipate further endorsements for campaign finance deregulation in federal, state and local elections.