A conservative legal advocacy group, Koch-backed, filed a suit against the Trump Administration on Thursday regarding emergency tariffs placed on China.

The New Civil Liberties Alliance filed a legal challenge against President Donald Trump’s “unlawful effort” to impose tariffs upon China under the International Emergency Economic Powers Act of 1977. NCLA filed a lawsuit in Pensacola federal court on behalf of Simplified. Simplified is a Pensacola-based company that buys products from China.

“In the nearly 50 years of its existence, not one president has attempted to use IEEPA for tariffs. This includes President Trump during his first term.” NCLA’s suit does not dispute President Trump’s declaration that an opioid emergency exists but does question his decision to impose tariffs without legal authority.

Trump announced on Wednesday that China will be hit with 34% tariffs in addition to the 20% he imposed earlier this season. This brings the total levies up to 54% and is close to the 60% figure that he threatened during the campaign.

As part of a new 34% tax, Chinese exporters are subject to a 10% base tariff on nearly all goods sent to the largest consumer economy in the world. This will take effect Saturday, before the higher “reciprocal” tariffs come into force from April 9.

NCLA says this is the first lawsuit filed over Trump’s tariffs against China.

“No previous president thought that the IEEPA would allow him to set tariffs. This law would be interpreted too broadly to allow the China tariff. It would also transfer legislative power. To avoid this nondelegation pitfall the court must construe it consistent with almost 50 years of unbroken practices and decide that it does not allow tariff setting,” NCLA president Mark Chenoweth stated in a press release.

NCLA presents itself as an independent nonprofit organization but receives funding from conservative Charles Koch and Leonard Leo.