The video is jarring: A gray-haired woman tumbles, gets up to reach for her phone, held by police officers, and is yanked and taken to the ground. “Are you kidding me?” a bystander asks.

“What are they doing to her?” another adds.

Annelise Orleck, a labor historian who has taught at Dartmouth College for more than three decades, was at a protest for Palestinians in Gaza on Wednesday night, when she was knocked to the ground. Dr. Orleck, 65, was zip-tied and was one of 90 people who…