The Supreme Court on Tuesday ordered the closure -- at least temporarily -- of a loophole that allows certain nonprofit political groups who spend on political ads to not disclose their donor lists (commonly referred to as "dark money").

The loophole was established nearly 40 years ago by the FEC, and became a focal point for campaign finance reformers after the 2010 Citizens United decision.

The NPR reports:

"The court set aside an order issued by Chief Justice John Roberts on Saturday. The social welfare group Crossroads GPS, a defendant in the lawsuit, had fought to stall disclosure while it prepares to appeal. It failed in the D.C. Circuit Court of Appeals and then appealed to the Supreme Court.

The disclosure requirement is expected to apply to explicitly political ads by nonprofit groups for the remaining weeks of the campaign season."

Read the full report here.

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