What is the test for a defamation claim?

"Whether published material is reasonably susceptible of an interpretation which implies a provably false assertion of fact --- the dispositive question in a defamation action -- is a question of law for the court. [Citations.]" In all cases, "[t]he dispositive question for the court is whether a reasonable fact finder could conclude that the published statements imply a provably false factual assertion. [Citation.]" (Moyer v. Amador Valley J. Union High School Dist. (1990) 225 Cal.App.3d 720, 724-725; Couch v. San Juan Unified School Dist., supra, 33 Cal.App.4th at p. 1500.) "Courts must be cautious lest we inhibit vigorous public debate about . . . public issues. If we err, it should be on the side of allowing free-flowing discussion of current events. We must allow plenty of 'breathing space' for such commentary." (Rudnick v. McMillan (1994) 25 Cal.App.4th 1183, 1193.)