The ruling, from U.S. District Judge Peter J. Messitte in Greenbelt, Md., will allow the plaintiffs in the case — the attorneys general of Maryland and the District of Columbia — to proceed with their case, which says Trump has violated the Constitution’s little-used emoluments clause.

The plaintiffs now want to interview Trump Organization employees and search company records to determine which foreign countries have spent money at Trump’s hotel in downtown Washington.

The Justice Department and Trump’s attorneys did not immediately respond to requests for comment. They could try to appeal the decision to a higher court and ask Messitte not to allow the attorneys general access to Trump Organization employees and books until the appeal is decided.