Our capacity to promise a safe and even-handed environment on our campuses is a tool of our public diplomacy.

There are a number of angles to the Mahmoud Khalil case, in which the Trump administration is trying to deport a green card holder for his involvement in pro-Hamas agitation at Columbia. This can be a murky gray area of the law, falling as it does at the intersection of free speech and the nearly absolute authority of Congress to exclude or expel foreigners from the country. Much will depend on the particular facts of how far Khalil’s conduct can be said to have departed from mere expression of opinion to the facilitation of illegal activity and/or Hamas fundraising and recruitment. Andy McCarthy has compared Khalil’s apparent role as negotiator or mediator between the law-breaking demonstrators and Columbia’s administration to the role of a mob consigliere in delivering threats — which can look like peaceful speech, but is backed by the unsubtle threat of violence.

As Andy has detailed, in all likelihood, Khalil will be deported if the government can meet the conditions for deportation in the statute, and not if it doesn’t; it’s far less likely, at least as a legal matter, that this ends with the courts concluding that Congress has authorized the deportation but that it nonetheless violates the Constitution. If the government cannot produce evidence that Khalil has met one of the specific statutory definitions of proscribed conduct (such as providing material support to a designated terrorist organization or being “a member of or affiliated with the Communist or any other totalitarian party (or subdivision or affiliate thereof), domestic or foreign”), the strongest ground may be a provision of the statute allowing for the exclusion of “an alien whose entry or proposed activities in the United States the Secretary of State has reasonable ground to believe would have potentially serious adverse foreign policy consequences for the United States.” There’s a procedural wrinkle: if Marco Rubio makes such a determination about Khalil, he “must notify on a timely basis the chairmen of the Committees on the Judiciary and Foreign Affairs of the House of Representatives and of the Committees on the Judiciary and Foreign Relations of the Senate of the identity of the alien and the reasons for the determination.” It does not appear that he has yet done so, but “timely” does not appear to be explicitly defined in the statute (I confess I have not checked to see how much time Rubio has).

In any event, let us assume for the sake of argument that Rubio invokes this provision, that he satisfies the procedural notice requirement, and that he has to make his case without more damning evidence of Khalil satisfying the more specific buckets of conduct described elsewhere in the statute. Let’s assume, for now, that he can only be proven to have been significantly involved in the Columbia protests, without having personally participated in the specific acts taken by the protesters that are easily defined as crimes, such as destruction of property or taking hostages. What would Rubio’s best argument be for ordering Khalil to be excluded from the country?

The mere fact of involvement in a protest against American foreign policy, or against an ally supported by American foreign policy, clearly isn’t enough. Everybody on the planet knows that Americans tolerate a lot of dissent, even very obnoxious dissent. It helps rather than harms our foreign policy that we have this reputation; even when the occasional despotic ally finds it uncomfortable, it is the cost of doing business with the United States.

Legalities aside, I don’t think it would be prudent to kick out of the country anyone who participates in an anti-Israel demonstration. That said, I’d favor excluding all opponents of Israel from the country as a matter of immigration policy. Being opposed to the State of Israel (by which I mean not every critic of some aspect of Israeli policy, but people who effectively side with its enemies) is very strongly correlated with opposing the United States and rejecting its core constitutional and civilizational values. Anyone can become an American if they want to, but we have no obligation to let people in who just want the protections America offers but do not actually want to become Americans.

In any event, the Columbia protests went far beyond merely registering public dissent. The characteristic shared by the pro-Hamas Columbia protests with the very worst of the pro-Hamas protests on other campuses is that they combined two factors going beyond the general expression of opinion. One is the breaking of laws and/or school rules in order to thwart the operation of the university. The other is the targeted harassment of Jewish students. Taken in combination, those two factors created an atmosphere on the campus that made it harder for Jewish students to pursue their education and enjoy the liberty of America because they were identified with a foreign ally of the United States. In the case of both American and non-American, non-Israeli Jews, that identification comes through religion and ethnicity; in the case of Israelis, it comes through their national origin.

When you consider it in those terms, you can see the threat posed to U.S. foreign policy by such harassing protests, and why such a threat can apply beyond the case of Israel. If protesters can shut down campuses and terrorize individual Jewish students in order to oppose our friendship and alliance with Israel, can they do the same to Taiwanese students? South Korean students? Ukrainian students? Saudi students? Turkish students? Mexican students? Indian students? Irish students? There are Americans of many ethnic and religious backgrounds on our campuses, and there are also a great many foreign students here — including the children of the governing elites of many foreign countries. Indeed, more than a few foreign heads of state studied in the United States themselves. Our capacity to promise a safe and even-handed environment on our campuses — not safe from free speech, but safe from mobs chasing down students or obstructing schools from operating — is a tool of our public diplomacy. Secretary Rubio would be on strong footing if he makes that argument the centerpiece of his case for deporting Mahmoud Khalil.