The United States Supreme Court has declined to intervene in a challenge to President Trump’s authority to enact steel and aluminum tariffs for stated reasons of national security. The president has claimed authority to implement tariffs pursuant to section 232 of the Trade Expansion Act of 1962, as amended. A challenge to the president’s section 232 authority was initially brought before the United States Court of International Trade (CIT) by the American Institute for International Steel (AIIS) and others (collectively, “Petitioners”). The CIT upheld the constitutionality of the tariffs, and Petitioners had asked the Supreme Court to take the case directly, thereby bypassing the interim step of having the case heard before the United States Court of Appeals for the Federal Circuit. On June 24, 2019, the Supreme Court announced that it would not bypass the Federal Circuit.

The crux of Petitioners’ claim is that Congress unconstitutionally delegated authority to the president under section 232 because that delegation lacked an “intelligible principle.” According to the Petitioners, because the statute is allegedly unconstitutional, the president could not use the statute as the basis for the tariffs.

The Supreme Court’s refusal to intervene does not mean that the challenge is over. Petitioners have stated their intention to continue the dispute via the normal appeals process before the Federal Circuit, with the subsequent decision appealed again to the Supreme Court if necessary. However, the Court’s refusal to take the case now is not a promising signal for Petitioners in what was always going to be a difficult argument to sustain. There has not been a successful challenge to legislation under the “nondelegation doctrine” for nearly a century. Moreover, the case involves a subject area (national security) where courts have typically been highly deferential to the executive, and the Supreme Court previously ruled that this very statute was a permissible delegation of authority by Congress.