Harvard president Alan Garber said Wednesday during an interview with NBC News that he had no choice but to fight the Trump administration over its decision to pull funding.

The president of Harvard on Wednesday defended the university’s decision to sue the Trump administration, adding that the institution “cannot compromise” on core principles like the First Amendment. Harvard took legal action against the Trump administration on Monday over the government’s decision to freeze over $2 billion in federal funding meant for the university after it refused to make the reforms it ordered.

The Trump Organization fired a conservative lawyer who served as its ethics adviser hours after the president attacked him for helping Harvard University sue the administration. The lawyer, William Burck of Quinn Emanuel Urquhart & Sullivan,