I wasn't referring to 'winning' anything. You are right that in American history the side that said we needed social security won and we have it.
But I was referring to the point in conversation when something becomes an opinion. An opinion on whether that cost is justified. Some think it is, others disagree. Economics can answer what is likely to happen under each situation, but it is still an opinion of which one is better than the other. Not saying that that opinion cannot be discussed or changed, my personal opinions change all the time. Just that the conversation is quite different at that point.