I'll say what people have been dancing around, or unable to say; The U.S is the lesser of the evils. Is the U.S perfect? Hell no. But they're the "least bad" country to be handling the system. Any other country or entity would immediately be targeted and open to bribing, gaming, pressure, and corruption.
We can look at historical examples like mercantile law. Most countries, including the U.S., recognize mercantile law, a body of law that has been handed down from millennia ago and, like so-called international law, distinct from domestic bodies of law, even though many countries have explicitly or implicitly incorporated aspects of mercantile law.
If you look at the history of judicial decisions where courts ruled in favor of non-citizen claimants, or where they adopted rules less favorable to citizens, then the U.S. doesn't stand out as much as you think. It's certainly at the top, but other, smaller countries have legal and political cultures that have respected mercantile law at the expense of their homegrown legal principles, and against the immediate best interests of their citizens and industry, at least as well as the U.S. has.
The real question is how good is a country's political and legal system at respecting abstract legal boundaries, especially in the face of strong, competing interests. Being large and powerful can often be a detriment because domestic competing interests are more powerful, and threats of repercussions less worrisome. Some smaller countries often have a better track record at keeping perspective; they have to be more honest about what reasonable solutions look like if they want to maximize their own, long-term wealth.
Based on mercantile law we can exclude many countries with solid arguments supported by decades and even centuries of concrete evidence. But arguing that the U.S. is the best (or least worst)? Again, that would be hard.
> England? Canada? Switzerland? Brazil? S. Africa?
You feel those countries are strong enough, politically and even militarily to resist corruptive influences? England might be, maybe Canada since the U.S is next door, but Switzerland, Brazil and S. Africa? No way. People forget; the U.S is incredibly powerful. It has the strongest military in the world. Nobody has attempted to "mess with the internet" because it meant messing with the U.S. Take it away from the U.S and it immediately becomes more vulnerable by default.
The US might be well positioned to withstand outside influence, but how do you expect the rest of the world to put their trust in a country where an insane, unstable fascist who has expressed his clear intention to violate international law is a realistic choice as leader?
