What is the test for a claim for municipal liability for failing to protect an individual's constitutional rights?

To state a claim for municipal liability for the failure to protect an individual's constitutional rights, the plaintiff must establish facts indicating the following: (1) the plaintiff possessed a constitutional right, of which he was deprived, (2) the municipality had a policy, (3) the municipal policy amounts to deliberate indifference to the plaintiff's constitutional right, and (4) the municipal policy is a moving force behind the constitutional violation. Oviatt v. Pearce, 954 F.2d 1470, 1474 (9th Cir. 1992).