Massive coordinated high risk commando raids and aerial bomb attack. The commando raids have a very brief time to disable known launch sites before the simultaneous strikes from the air. If the air strikes fail, they continue the effort. Thousands of smart missiles have to be used along with all available stealth bombers to hit all known and suspected targets at once. Following that, all available bombers have to target every bridge, tunnel, dam, non-nuclear power plant, railroad, antenna, communication line, power line, government building, military site, fuel depot, laboratory, and any other structure that enables the Pakistani military to operate. India will maintain non-stop shelling of their border to stop refugees from heading in that direction. The US will have to do the same along the border with Afghanistan and Iran. In this very dangerous airspace, fighter jets have to knock out any Pakistani aircraft that gets up, while low altitude craft secure select airfields for the injection of infiltration troops. These troops support commandos and intelligence operatives who grab high profile targets, extract nuclear weapons materials, and secure nuclear power facilities. The bombing campaign continues until Pakistan reaches the Stone Age. There may be a little blowback when millions of people die of starvation and disease in the following year.
It could fail. But there only around 100 warheads to take out, some number less than that ready to launch. If those can be taken out in the initial attack the chance of succesfully preparing and delivery of a warhead dimishes rapidly. Since this could not be done in a practical manner without the cooperation of China, India for active cooperation, along with Russia, NATO, and others for intelligence/counter-intelligence purposes, it is unlikely to ever launch. But I’m sure we contigincy plans of this nature prepared and maintained for this event, and probably based on a short preparation period with much less hardware and international cooperation available.
I doubt it, since it has virtually no chance of working. All it would be likely to do is guarantee a launch; and moving that many troops in close just gives them concentrations of Americans they can target those nukes against. More likely any contingency plans we have are something like “move American troops out of range and hope things settle down”, or “nuke everything vaguely military”.
It is overly ambitious, and highly risky. But the only reason to try and disarm Pakistan is because there is a greater threat of a nuclear missile attack if we don’t. In that circumstance we’d go with the military strike to attempt to eliminate that possibility. I’m not saying it’s good idea to disarm Pakistan right now. Our greatest need is stop them from using nuclear weapons, not having them.
As I mentioned a few actions back, the only justification for taking action would be to stop the imminent threat of an attack, so I wouldn’t consider that a war crime myself. But I don’t see these circumstances as real. It’s doubtful we would have advance notice of an imminent launch that would justify pre-emptive action, and doubtful that we would get the cooperation we needed. We’d be much better off trying to keep Pakistan from getting to the point where they would launch in the first place. But if we were stuck between a rock and a hard place, we’d want to try and stop an attack.