No, no... The problem is more basic than that. Consider this: How should we decide on whether to implement a protectionist policy, if the producer and consumer

No, no... The problem is more basic than that. Consider this: How should we decide on whether to implement a protectionist policy, if the producer and consumer don't agree on the relative costs vs. benefits? Naively, just ask the producer(s) to put a price number on how much financial benefit they'll receive... And then ask the consumer(s) to assign a price number to their costs. The government compares the two numbers, and if the benefit of protection to producers is higher, our government implements the policy. Ok, but in practice, the financial impacts of trade policy changes are really hard to quantify, especially in advance. We don't have any obvious, objective signals like public market prices, so you'd have to dig into the business models and accounts of both domestic AND foreign firms. Public filings won't provide the right data, you'll likely need access to the confidential details that underlie their public reports. Also, you needs to assess the behavior of consumers in response to the new policy, potentially on a mass scale. You need detailed data on historical consumer behavior, plus a prediction model. Oh, and you need to predict the future of the world economy, how major events will transpire going forward, how foreign governments/firms/consumers will counter your policy... And then model the impacts of all that on consumer/producer behavior. ... Anyway, point is: Humans don't actually have sufficient tools to evaluate the specific financial effects of trade policy changes. Our best, brightest, most well-informed analysts can make some aggregate guesses, but in the real world the analysts are right almost as often as they're wrong. Hypothetically, IF we had a relatively reliable, accurate ability to evaluate the impacts, we could make policy that way. But we don't, so we don't. Moral arguments that rely on such a capability are just wishes for horses.