A federal judge in Montana on Thursday blocked a statewide ban of TikTok from taking effect next year, at least temporarily preventing the nation’s first such prohibition on the popular video app.

The judge, Donald W. Molloy, said Montana could act as a leader in protecting its residents from harm but must “act within the constitutional legal context,” and he granted a preliminary injunction to stop the TikTok ban. He said a ban of the Chinese-owned app most likely violated the First Amendment and a clause that gives Congress the power to regulate commerce with foreign nations.

“The current record leaves little doubt that Montana’s Legislature and attorney general were more interested in targeting China’s ostensible role in TikTok than with protecting Montana consumers,” Judge Molloy wrote in his opinion. He added that Montana’s “foray into foreign affairs interprets the United States’ current foreign policy interests and intrudes on them.”

Alex Haurek, a spokesman for TikTok, said the company was “pleased the judge rejected this unconstitutional law and hundreds of thousands of Montanans can continue to express themselves, earn a living and find community on TikTok.”