The American Institute for International Steel (AIIS) [corporate website] filed a lawsuit [complaint, PDF] in the US Court of International Trade [official website] on Wednesday against the United States and US Customs and Border Protection Commissioner Kevin McAleenan against steel tariffs imposed by US President Donald Trump in March.

The lawsuit seeks an order from the court enjoining the US from enforcing the 25 percent tariff increase for imports of steel products and other trade barriers imposed by Presidential Proclamation 9705 [text].

The complaint argues that the tariffs are an unconstitutional, improper delegation of legislative power to the President, “in violation of Article I, section 1 of the Constitution and the doctrine of separation of powers and the system of checks and balances that the Constitution protects.”

Injuries to the members of AIIS cited in the complaint include irrecoverable losses to companies, workers, unions, port authorities, customs brokers, insurance companies, logistics companies, among others.