Why, the #1 nation, of course.

My title became too much of a clown car, so I had to remove the country. (I didn't dream that it wasn't in the article!)

The nation that designed and built the largest nuclear weapon ever detonated, that produced the most powerful human-made explosion ever recorded?

That was Russia.

"the #1 nation" depends so much on metric.

Norway leads the https://en.wikipedia.org/wiki/The_Economist_Democracy_Index

Switzerland leads the https://worldpopulationreview.com/country-rankings/freedom-i...

Australia leads the US in the US's own "best country" ranking https://www.usnews.com/news/best-countries/rankings

I think it was said tongue-in-cheek