The arrest of Mahmoud Khalil, a Columbia University student and anti-Israel activist, tests President Donald Trump’s new policy to deport foreign nationals backing terrorist groups. The first case of its kind, it has ignited media frenzy and protests. How it unfolds could significantly influence the political climate during the initial phase of Trump’s second term.

Khalil, a green card holder, was highly visible in his role as lead negotiator during the “Gaza Solidarity Encampment” protests on behalf of the activist group Columbia University Apartheid Divest. This group has made numerous statements of support for Hamas’s terrorist attack in southern Israel on Oct. 7, 2023, at one point calling it a “political, military, and moral victory.” This would appear to provide Secretary of State Marco Rubio with “reasonable grounds to believe” Khalil’s presence in the United States could have “potentially serious adverse foreign policy consequences,” which is the standard under the Immigration and Nationality Act of 1952.