Spying on a country to country level is good for international relations. It's a hacked version of transparency. Since the countries of the world won't really agree to be transparency, intelligence is the next best thing.

The unknown causes fear and conflict. Much of the cold war was driven by deep mistrust of the other side. Spying eases tension by leaking the plans of each side. If the Russians know what the US military is doing, it doesn't have to be fearful. If the US knows what Russia is doing, it doesn't have to be fearful.

So now, if the US knows Putin isn't going to push for a full out invasion of Ukraine, the US won't escalate the crisis.

If Obama knows Iran's government feels the pain from sanctions, he can have a real conversation about nuclear development.

Iraq, one of the biggest international disasters since the Berlin Wall fell, was caused by shitty intelligence and fear of the unknown. Saddam really dismantled his WMD program, bu the US, based on fear, assumed he was hiding it.

This is totally different than a surveillance state over the individuals.