How weak is the commitment to free speech on US campuses? Well, at Middlebury College you can riot against an invited speaker, assault him and his faculty host, actually put the professor in the hospital — and it doesn’t even go down in your permanent record.

Credit John Leo of the Minding the Campus blog with exposing the Vermont school’s “punishment” for dozens of students who ran wild to stop scholar Charles Murray from speaking back in April.

The demonstrators stopped the speech (he was able to deliver it only via an online broadcast), then chased Murray and his host across campus, threw a concrete block in front of their car and finally mobbed them both — hospitalizing the prof, Allison Stanger, with neck injuries.

Discipline for the worst offenders has yet to be determined, but most of the students are getting off with . . . a letter of condemnation in their school file, to be removed at the end of the semester.

All in all, “punishment” that pretty much invites the goons to strike again.