Err. no
This is not the biggest issue
Yes, it is.
1) North Korea honchos are not exactly living in a palace where they can be take off easily. And the military infrastructure of North Korea is quite extensive and well protected so in order to take everything off the US would need to find a number of bases around NK and be prepared for a long aerial campaign. From a sheer economic point of view, the US is now not in the condition of doing this
A large portion of work would be done by South Korea anyway. US is well able to afford it, although it would prefer not to.
2) An attack to NK would require the OK from the UNSC which would be blocked by China. So the US could still go ahead and do it but it would be an act of aggression. The United States, especially after the disaster in Iraq, can not afford to be seen as an aggressor by the international community as an aggressor again
Nonsense. Any action against North Korea has had the blessing of the UN since 1950. There was no peace treaty, only a cease fire that North Korea declared was null and void two years ago. There are zero legal requirements to attack North Korea.
3) China is heavily supporting North Korea. China` s military is quickly improving and they have a military budget now about half that of the US. A large number of domestically manufactured planes, aircraft carriers, destroyers and one of the largest in the world arsenals of nuclear weapons in the world. Considering that the United States could not force militarly Iran to abandon their nuclear program, it is impossible for them to force North Korea to surrender, considering that China would almost surely support
The number of assumptions and outright falsehoods here is astounding. China doesn't have a large number of domestically manufactured planes (relying on license produced Russian export junk), aircraft carriers (one, Soviet produced, semi-submersible). They have domestic produced ships of untested quality, and a nuclear arsenal that is not particularly large, but it's also not trivial. They have no long range power projection capability, no long range aircraft, a very limited submarine force, hostile relations to almost all neighbors and no allies to speak of.
China has already stumbled heavily in their empire-building. Their economic growth, as always, brought aspirations for personal liberty as well. Chinese government didn't cooperate, so it did the thing countries in such situations do: invented foreign enemies and started foreign conflicts, in order to silence the opposition and divert attention. The result is that Vietnam and Philippines - two potential natural allies to the Chinese - are driven into the embrace of the US. The same goes for all other countries in the South China sea, which would be valuable allies to China, but instead prefer the US.
The main issue with China however that it's very doubtful China would be willing to go to war with it's largest trading partner, in order to defend
North Korean regime. They would likely welcome what the effects would do to South Korean and US economy, but wouldn't intervene.
4) An attack to NK by the US would start a confrontation with the no. 1 economy of the world, China, which is growing at 7%. The US can not win the battle
Sure, keep telling yourself that. Especially the "can not win" part. Laughable. Chinese forces are capable of fighting off a US naval invasion and occupation of China, but their relative capabilities fall dramatically in any other scenario.
As for Chinese economy, you probably don't want to hear this, but it's not 7%, and probably hasn't been anywhere near 7% for quite a while. But that's a story for another thread.
McHrozni