I have an idea. Expel the trouble makers and have them all arrested.
I have a better idea. Midnight basketball!
This is actually what should be done. Inform those issuing threats that the administration will not be coerced into any policy changes, and any student who engages in "physical action" will immediately be expelled and subjected to any applicable criminal charges. However, this is the Univ of Michigan and its spineless Liberal leaders and faculty will quite probably cave to the mau mau tactics of the black agitators.
That was my first thought as well.
So right. If they're expelled, they have no "standing" on the campus.
Then issue a statement saying the University is committed to the education of its students, and will not tolerate those who would disrupt its mission.
In a sane world, that would be quite enough ...