A nuke isn’t plausible deniability. They, and the balloon, can be tracked back to source.
Someone in another post was worried about balloons dropping bombs. Guided glide bomb would be pretty effective. But the balloon isn’t stealth. As we’re seeing, even small objects can be tracked by radar. Also, bombs are heavy and that means a large balloon. Something the size of the ground visible spy balloon.
Infrastructure is more resilient than you think. I doubt there is a spot where a single bomb could cripple things. If there was, a ground bomb would be effective and easier.
The continuous monitoring today makes even underground tests attributable to certain counties. We can tell when the North Korean announcement of a nuclear test happened to not coincide with even vanishingly small amounts of radioxenon.
And, forensically, what’s left behind after an explosion tells the design and mix of fissile material, which tells you the level of resources available to the maker.
Not sure I believe that it can be done beyond a reasonable doubt. I still don't see what evidence there is that these things are Chinese. It's probably speculation and nothing more. It might still be true, but the attribution is likely highly speculative.
Balloons move with wind and can track the winds back to origin. I guess we can’t figure how far back the origin was but can make a guess.
Another thing is that other countries have radar. They likely tracked the balloon but ignored it. Russia probably won’t help but Japan might have seen it. Also, US is tracking balloons from before they enter Alaska.
We know the balloon is Chinese because they claimed. We don’t know what the other objects were.
Someone in another post was worried about balloons dropping bombs. Guided glide bomb would be pretty effective. But the balloon isn’t stealth. As we’re seeing, even small objects can be tracked by radar. Also, bombs are heavy and that means a large balloon. Something the size of the ground visible spy balloon.
Infrastructure is more resilient than you think. I doubt there is a spot where a single bomb could cripple things. If there was, a ground bomb would be effective and easier.