Is probable cause to arrest an affirmative defense to a claim of false arrest?

¹ Under California law, probable cause to arrest is an affirmative defense to a claim of false arrest. See Miller v. Glass , 44 Cal.2d 359, 282 P.2d 501, 503 (1955) (explaining that lack of probable cause has "no bearing ... on charges of false arrest and imprisonment, except ... where the offense is apparently being committed in the presence of the arresting officer, he may invoke by way of defense the doctrine of probable cause to justify the arrest without a warrant" (emphasis added) (citations omitted) ).