Biden nominated Boardman to the seat vacated by Judge Richard D. Bennett, who had announced his intent to assume senior status upon the confirmation of his successor.

[12] On August 24, 2023, Boardman denied a request for a preliminary injunction seeking to reinstate a Montgomery County School Board policy that previously allowed parents to remove their children from lessons involving books featuring LGBTQ characters.

[13] Plaintiffs claimed the exposure to these books “contradict their sincerely held religious beliefs about marriage, human sexuality, and gender” and that the lack of an opt-out policy violates their children’s First Amendment right to free exercise of religion.

[16] On August 19, 2024, Boardman ruled in favor of environmental groups, including the Sierra Club, which challenged a biological opinion issued by National Marine Fisheries Service in 2020 under the Trump administration.

Boardman found the agency violated the Endangered Species Act and the Administrative Procedures Act by underestimating risks and failing to implement adequate mitigation measures concerning the effects of oil spills in the Gulf of Mexico on protected species, including the Rice's whale.

[19][20] The following day, Judge John C. Coughenour issued a similar preliminary injunction in a case filed by the State of Washington challenging the same executive order.