We can only gain by spying on you. We have a military base with defense systems in your country. Your political decisions therefore will have an impact on the effectiveness of our military system to defend our country.
Except for a lot of damage to goodwill, which can have an economic impact. Lots of European citizens dislike the US heavily now and that comes with disliking US products.
Your political decisions therefore will have an impact on the effectiveness of our military system to defend our country.
First, the US and Germany are allies. Allies talk and don't spy. Second, by now it's clear that a lot of the espionage is economical.
The US/NSA mistreated their allies. It will take many years to rebuild trust.
If you want to figure out a world where people aren't self-interested and risk-averse, maybe a church would be a better place for you to have that discussion.
And I agree that most if not all decisions are based or should be based on the expected gain, but the question is then of course how you define or measure that gain. There may actually be a real gain for a country if you spy on other countries, but I argue that this is the wrong standard for gain in that situation, a selfish definition of gain. I would strongly prefer to consider the gain or loss for the whole world when evaluating decisions like whether or not to spy on other countries.
The point seemed to be: "just because it has a pro, doesn't mean I should do it". I could use the same logic to state that I can only gain by spying on my friends as well. Does that mean I should? Does that mean it has no downsides?