Let me be clear it doesn’t make sense for USA or PRC to use nuclear weapons at this time. There’s simply no need to escalate all the way.
Combine this with the Ohio derailment and the uncaught substation snipers which knew an awful lot about what equipment to take out.
Derailment is a powerful sabotage tool. Americans were caught attempting it in Russia years ago. https://tass.com/politics/1313063
They are trying to weaken infrastructure by making taxpayers bleed time, money, and effort.
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.
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.
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.
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.
Actually, looking at current high altitude wind patterns [1] it looks like launching a high altitude balloon anywhere in a large chunk of the Northern Hemisphere will get it to the Northern US, including most of the Mideast, which includes many of the places with people that would love to do a terrorist attack on the US. If one of those places did it, though, their balloon would have to pass over Russia and/or China so probably wouldn't go undetected like a North Korea launch might. Russia and/or China might not be happy to be used that way.
[1] https://earth.nullschool.net/#current/wind/isobaric/70hPa/or...
In order:
Signals intelligence proximate to the plan's inception that'd likely thwart things before the situation escalated
Monitoring of the incoming track and its electromagnetic emissions
Observation of the blast from a variety of sensor platforms
A WC-135 flying near the atmospheric blast area to determine isotope composition
The problem with that scenario is that the US would respond as if nuke was used on the ground.
The balloon is just delivery mechanism for their fears. Could be equally worried about private jets.