Protesters sang and held signs Thursday to support Kilmar Abrego Garcia before a court hearing in Maryland.

A federal judge is hearing arguments over whether Abrego Garcia can be deported to Liberia or whether the government is legally required to respect his designation of Costa Rica as the country where he wants to be sent if forced to leave the U.S.

The Salvadoran national's mistaken deportation to his home country in March helped galvanize opposition to President Donald Trump’s immigration policies. Abrego Garcia's attorneys claim the administration is now manipulating the immigration system in order to punish him, a violation of his due process rights.

The government argues that his due process rights are minimal because he entered the country illegally. A federal judge in Maryland has temporarily blocked Abrego Garcia's deportation. The government is asking her to dissolve that order.