Does the use of pepper spray on a peaceful protest constitute excessive force in violation of the Fourth Amendment?

As the cases just discussed indicate, the unreasonableness of this use of force was clearly established at the time of the protest. That conclusion is inescapable even if we focus only on one aspect of the force used. The protestors allege that the police officers used pepper spray bullets, even though the demonstrators were peaceful and cooperative. It was clearly established at the time of the protest that the use of pepper spray on an individual who is already under control constitutes excessive force in violation of the Fourth Amendment. See Headwaters Forest Def., 276 F.3d at 1130;LaLonde v. County of Riverside, 204 F.3d 947, 961 (9th Cir.2000).