The supreme court has allowed the US Department of Defense to take disciplinary action against an air force lieutenant colonel who refuses to get a Covid-19 vaccine.

In a brief, two-sentence ruling on Monday, a majority of the court sided with the Pentagon. Three justices in the conservative majority – Clarence Thomas, Samuel Alito and Neil Gorsuch – dissented.

The ruling was merely the court’s latest on challenges to Covid-19 vaccine mandates.

In January, the court blocked a Biden administration requirement that employees of large businesses be vaccinated and wear masks on the job.

The court ruled in March that the US navy had the authority to determine the job assignments of 35 service members who refused to get vaccinated.

The case in question on Monday involved Lt Col Jonathan Dunn, previously commander of a 40-member squadron in California, according to court documents filed by the US solicitor general, Elizabeth Prelogar.

Prelogar argued that while Dunn cited religious grounds for his refusal to get vaccinated, he did not “assert that the Covid-19 vaccine or compulsory vaccination in general is inconsistent with his Christian faith”, noting that he has received other vaccinations without objection.

Dunn instead cited a speech given by Joe Biden that led him to conclude that “the vaccine ceased to be merely a medical invention and took on a symbolic and even sacramental quality”.

His religion, he said, forbade him from participating in such “religious ritual”.

Upon denial of his exemption request, Dunn sent to a major general “a one-word memorandum that simply read: ‘NUTS!’”.

Prelogar noted that while Dunn maintains he meant no disrespect, “NUTS!” has a “well-known ‘military historical connotation’”.

She cited the case of Anthony McAuliffe, a key US military officer in the second world war who responded to a German message requesting American surrender with the one-worded answer. The American officer who delivered McAuliffe’s message to German officers clarified that, “If you don’t understand what ‘nuts’ means, in plain English, it is the same as ‘Go to hell.’”

The court documents say that the air force took disciplinary action against Dunn, including his removal from command and non-punitive disciplinary measures, citing his commanding officer who said he had “lost trust in [Dunn’s] leadership and judgment” due to the memorandum and that he displayed a “pattern of a lack of respect for military authority”. Prelogar said that Dunn’s actions independent of his refusal to be vaccinated warranted the measures against him.

The US solicitor general also said that Dunn’s unit has to be ready to be deployed anywhere in the world with as little as three days’ notice, including countries that require proof of vaccination for entry. Prelogar also noted that the military has a long history of requiring vaccinations and currently requires nine vaccinations for service members.

The deadline for air force members to get vaccinated was 2 November. In December, an air force spokesperson told NBC News that the military branch discharged 27 active-duty members who refused to get the vaccination and were not exempted. The US military that same month said 97% of its service members had received the Covid-19 vaccine.