No Stupid Questions

Because - improbably, given its track record elsewhere - the world has worked out that the solution to someone killing kids isn't to kill more kids.

Because China doesn't want anyone to.

Nukes. We know they have them and missiles to deliver them. Any situation where a wildcard like North Korea uses nukes in any offensive capacity is terrifying. "Nuclear War: A Scenario" is a great modern book on how things could go to hell if one single North Korean nuclear missile is launched towards the United States.

Artillery. In any case of open war on North Korea anyone within artillery range of the NK border will be bombarded with heavy shelling. Even if it lasted for just an hour or two before the batteries were eliminated the civilian casualties and destruction would be like a large natural disaster. Now imagine if chemical shells were added to the mix, because they have those too.

China has the most leverage to help North Korea on a humanitarian and diplomatic level without risking war, so if it could be done the best chance is through them.

Feel free to pitch the idea to congress. It will cost somewhere in the realm of trillions of dollars to invade, occupy, and rebuild North Korea. We're talking an occupation lasting decades. A full time military presence for the foreseeable future as North Korea rebuilds something resembling a functional democratic society.

Don't get me wrong, their military would get absolutely bodied in a full on shooting war with any sort of NATO-esque military coalition. But they have a sizable entrenched force with more than a few functional nuclear weapons. It would cost A LOT of lives.

So, that's the bill. If you think you can convince congress to go for it, go nuts.

China is the answer. Nobody does anything about North Korea for the same reason China doesn't invade Taiwan.

Are you familiar with the Korean war? There was a massive conflict which got drawn out into a stalemate and everybody agreed a temporary ceasefire was preferable to even more destruction.

Trying to topple a regime that has nothing to lose and a highly indoctrinated population is not an easy ask. We can only hope that like most authoritarian regimes they eventually succumb to the weight of their own opression. It's better than torching the whole continent in the name of freedom.

Seoul is so close to the border, it’s within artillery range of NK. Kim can cause all kinds of havoc without resorting to nukes. If provoked enough, he could put one (or more) craters in South Korea’s largest city, without even playing his scariest card.

Then there’s the possibility of a military response from China. Nobody wants to be on the receiving end of that.

Lastly, NK has been under all kinds of sanctions for years. It might not be the “anything” you have in mind, but many nations seem to be doing about as much as they can without risking all-out war.

Ah, the old question about what to do about North Korea, it occupies the minds of many, there are some answers, many lead to more questions, and so on.

The stakes are increadibly high, so we have to tread very carefully.

Let's bring up a few key facts.

1. NK is a totalitarian state with a huge personality cult surrounding the Kim family.
2. NK is supported by both China and Russia, they both have a highly vested interest in keeping the status quo.
3. NK is located within artillery range of SK's capital city, Seoul.
4. NK's society is vastly different from all of it's neighbours, even the language used in NK is noticably different from the language spoken in SK.
5. NK has nuclear weapons.
6. NK does not have a problem ignoring the normal rules of diplomacy.

Now, you ask what other countries can do to help the people of NK, that is a hugely complicated question, which in general is mostly answered with an answer no one really wants to hear:

Support the current regime

For any proper aid to get into NK you need the support of the regime, and they will take the credit for the aid.

I saw a documentary of a film crew following a team of surgeons travelling to NK to help people who had lost their sight, it was a simple operation, preformed and funded by foreign organizations, the regime had only allowed the team access.

The operation took maybe a few min per patient, they replaced a lens in the eyes of the patient, and as soon as the patient was done, they rushed to the portraits of the leaders of NK, got on their knees and thanked them deeply for their graciousness of restoring their eyesight.

This is the kind of society NK is, everything is tied to the leader.

This is the starting point, and you have 26 million people to deal with...

Ok, say that a world power decide that they have had enough with the Kim family and this is worth going to war over.

What can we expect?

Regardless of what countries are involved, Seoul WILL be bombarded.

So now the attacker is hated both in NK and SK as well as probably a lot of other countries.

NK will use their nukes, and possibly other WMD they have.

Then comes China....

China loves NK as a buffer against the west, so they would and have deployed the PLA to save NK.

We see and hear what the US state dept wants us to hear. And nothing more.

As to the core of your question. The answer is nukes. Nukes are the only way to fend off the imperial aggression of the United States and its imperialist partners.

Countries are not good or bad they don't have friends they have interests. Is always a good rule of thumb when thinking about Geopolitics.

The same reason you never hear from what happens inside abusive households until someone from within speaks up (aka: a "defector")

Edit: As for the follow up questions:

Imagine you live in the "hood" where the authorities doesn't do shit, and you see someone who's part of a gang abuse their child, are you gonna go confront them at the risk of getting your whole family shot to death? That's what MAD is like on the world stage. North Korea has China as an ally, don't forget about that.

One thing I have not seen brought up yet is that Seoul is within artillery range of North Korea. Even if North Korea didn't have nukes they could bombard the city with conventional arms or even chemical weapons and kill hundreds of thousands in the first day or two.