North Korea had enough conventional artillery to level Seoul with an estimated 1M casualties. That was why Clinton decided against attacking North Korea as they moved towards building the bomb:

https://nationalinterest.org/blog/reboot/north-koreas-artill...

Iran’s deterrent was/is through its proxies (Hamas, Hezbollah, Houthis) along with its sizable missile inventory, anti-air capabilities and strategic threats to oil and gas exports.

Israel’s investment in missile defense and the outcome of the Oct 7th attacks severely weakened Iran’s deterrence to a conventional attack.

I think the lesson should be that any nation that has enough conventional leverage to deter an attack could choose to build nuclear weapons. Nuclear weapons may complement, but can’t displace other capabilities.

The US has nuclear weapons but that didn’t deter Iran from launching direct attacks on US troops in the Middle East or sponsoring insurgents in Iraq. Nuclear weapons are also essential worthless against non nation-state actors such as Al-Qaeda.

I have become much more skeptical about DNK’s artillery after seeing the results of a frontline air-superiority stalemate in Ukraine and the Israeli campaign against Iran.

If South Korea’s coalition could establish air superiority over the DMZ and artillery range in the first moves, I think it takes you from “Seoul destroyed” to a “pretty average modern conflict.”

Hot take for sure, but war has changed.