Numerous states and non-governmental organizations filed suit shortly after the order, resulting in a Ninth Circuit ruling that deemed the transfer of funds inappropriate under the Appropriations Clause and leading to the Supreme Court challenge.

Trump's successor, Joe Biden, terminated the national emergency and ceased wall construction, making the case moot.

One of Donald Trump's presidential campaign pledges was to greatly expand and fortify the border wall to further restrict illegal immigration into the U.S.[1] Shortly after his inauguration to office in January 2017, Trump issued Executive Order 13767 instructing the government to begin construction of the expanded wall, but as the Order lacked any funding directive, no such construction could begin.

[5] Trump declared the National Emergency Concerning the Southern Border of the United States on February 15, 2019, two days after signing the 2019 budget into law.

The order directed that about US$8 billion of previously allocated funds from Congress to departments within the Executive branch be re-allocated to construction of the border wall.

Judge Gilliam issued a preliminary injunction in the Sierra Club case on May 24, 2019, blocking the use of the targeted funds for border wall construction on the basis that the plaintiff's challenge had a good chance of succeeding on the merits.

[20][21] The Trump administration petitioned the Supreme Court challenging the Ninth Circuit decision of both the Sierra Club and the states' case, questing both the standing of the plaintiffs in the original suits, and the authority for the re-allocation of appropriated funds pursuant to Section 8005 of 2019 NDAA was lawful.

[24] Subsequently, in orders on July 2, 2021, the Supreme Court granted the government's request to vacate the ruling from the Ninth and remand the case there to determine if any further litigation was required.