Chomsky writes about the expert effect in Manufacturing Consent. Basically, among credentialed experts on any given topic, you can find opinions going every wh

Chomsky writes about the expert effect in Manufacturing Consent. Basically, among credentialed experts on any given topic, you can find opinions going every which way. So bringing in an expert to bolster your point is meaningless, because they are brought in because of their preexisting opinions which as you note sometimes run against the rest of the field. Another technique is to bring in someone with contrary opinions and one with favorable opinions, and basically not give them much shot to speak or force them on the defensive for everything they say with both your expert and the moderator. Then you can say you soundly defeated that critical opinion of the topic.