The United States Supreme Court has granted Donald Trump’s request to ban transgender people from serving in the military.

The conservative majority court voted in favour 5-4, with four liberal judges on the court opposing the policy. Although the decision is temporary, this means that the Trump administration will be able to enforce the ban while the case proceeds.

“There is simply no way to spin it, the Trump-Pence Administration is going all in on its discriminatory, unconstitutional and despicable ban on transgender troops,” said HRC president Chad Griffin after the ruling.

Senior staff attorney at the American Civil Liberties Union LGBT & HIV Project, Joshua Block, slammed the policy and said it “effectively coerces transgender people who wish to serve into choosing between their humanity and their country, and makes it clear that transgender service members are not welcome.”

The President of the United States first took to Twitter in 2017 to announce that anyone who identifies as trans will no longer be allowed to serve their country, citing “tremendous medical costs” and “disruption” by trans individuals.

“After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow Transgender individuals to serve in any capacity in the US Military,” he wrote.

“Our military must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail. Thank you.”

Laverne Cox, trans activist and star of Orange Is The New Black, took to social media to blast the Trump administration, labelling the move “another example of the brutality of colonialism” and encouraging followers to support anti-discrimination laws.

“This latest administration effort to legislate trans folks out of existence is yet another example of why the fight for gender equity must be intersectional and necessarily must include trans folks,” she wrote.

“Trans folks need everyone to stand with us in this fight, to let our government know this is not who we are.”

And over 1,600 scientists, including nine Nobel Prize winners, have joined the backlash, by signing an open letter condemning the memo. Their letter, which was signed by over 700 biologists and 100 geneticists, was titled “Transgender, intersex, and gender non-conforming people #WontBeErased by pseudoscience.”

In the letter, they wrote: “The proposal is in no way ‘grounded in science’ as the administration claims. The relationship between sex chromosomes, genitalia, and gender identity is complex, and not fully understood.

“There are no genetic tests that can unambiguously determine gender, or even sex. Furthermore, even if such tests existed, it would be unconscionable to use the pretext of science to enact policies that overrule the lived experience of people’s own gender identities.”

The Supreme Court’s decision means that transgender people will have a number of challenging requirements in store if they want to serve their country. They can refuse potential recruits who have transitioned and have a history of ‘gender dysphoria’.

Related: Donald Trump’s approval ratings hit record low after the trans military ban.

Related: Trump administration is withholding information over its proposed transgender military ban.

Related: Mike Pence and anti-LGBTQ activists reportedly drafted Trump’s new transgender military ban.