There are, of course, other considerations, but Seoul would be very difficult to defend from 'simple' weapons like artillery. The US is very proud of it's ability to fire artillery 40 miles (64km), but Pyongyang is much further than that.
Everything I've read suggests the Seoul is a casualty of any conflict. Regardless of the eventual 'winner'.
Once someone on either side has been killed in war, both sides permanently lose. There are no take-backs, only damaged soldiers on both sides and casualties.
Both Seoul and Pyongyang are within range of their adversaries' weapons.
The point oblio is maintaining upthread is that because SK and her allies have much more advanced weaponry NK doesn't have a chance of standing against them in a conventional conflict. That's true, but misses the point.
Before NK had nuclear weapons one of their main deterrents was that they'd had years/decades to fortify conventional artillery at the border pointed at Seul. So even if their military couldn't stand a chance in a conventional war they could plausibly threaten MAD by holding Seul hostage.
That's the context in which the border proximity is brought up. Replying to that by saying that Pyongyang is 150 km from the border or whatever is irrelevant.
Yes of course the US could win an all-out conventional war with an enemy 50, 150 or 1500 km from its border. That was never in question.
The question was whether a relatively weaker enemy could present an outsized threat due to some strategic geographic position.
That's been the case with NK precisely because mid-century artillery technology can be dug-in close enough to the border to matter.
Whereas if the border happened to be 150 km away those assets could be taken out by missiles once they tried to move in position to shoot on a major target like Seul.
Whether the NK artillery actually poses a strategic threat is another matter. I wouldn't be surprised if it's all mapped out be the US/SK and would be taken out in the first 5 minutes of a conflict by targeted missile attacks.
But it's not just a strategic question, but whether e.g. NK can make threats that are taken seriously by the SK population for it to pressure its government to make some concessions to NK.
Sadly no. There are so many UGFs (underground facilities) on the JIPTL (Joint Integrated Prioritized Target List) and we don't have anywhere near enough ordnance of the right types staged to hit them all before Seoul is a smoking crater. I've participated in 5 or 6 of the big Korean Theater exercises[1][2], working at a Corps-level HQ. The entire country is a reinforced underground fortress. Remember how we shelled Iwo Jima for several days and still barely scratched the defences on Mt Suribachi? NK is like that, but worse. They've had 60 years to dig in, and instead of a small island a few miles wide, the fortress is the size of Indiana.
[1]https://en.wikipedia.org/wiki/Key_Resolve [2]https://en.wikipedia.org/wiki/Ulchi-Freedom_Guardian
This is not 1945.
Thats why diplomacy is the way forward. Our species cant go through a global war with countries outdoing each other to kill civilians.
I think we are in agreement here.
You are right that they might not use the same weapons, but long-range precision guided artillery is expensive. Because the shells are expensive, not all countries have enough to use them without limit as was the case in WW2 - where in the last few months of the Western Front the allies preferred to expend munitions rather than their own soldiers' lives.
This can definitely be done in both directions.