A federal judge ruled on Wednesday that US President Donald Trump's administration cannot use US foreign policy interests to justify its detention of Columbia University student and activist Mahmoud Khalil.
The judge said that Mr Khalil's legal team had shown that his continued detention is causing irreparable harm to his career, his family and his right to free speech. The government had until Friday to appeal.
Mr Khalil, who was a leader in campus pro-Palestine protests last year, is being held in an immigration detention centre in Louisiana after he was arrested in early March and threatened with deportation.
The State Department revoked his green card under a little-used provision of immigration law granting the Secretary of State the power to seek the deportation of any non-citizen whose presence in the country is considered to be adverse to US foreign policy interests.
The White House has also accused Mr Khalil of disseminating Hamas propaganda during the protests.
A judge in Louisiana had previously ruled that the US government could proceed with efforts to deport him. He was denied furlough in late April to attend the birth of his first child.
His arrest was part of a Trump administration crackdown on so-called anti-Semitism on university campuses. The administration has deemed pro-Palestine protests to fall under this umbrella.
Mr Khalil has described himself as a political prisoner and said that his arrest was indicative of anti-Palestinian racism in the US.
