how about you look into the history of the koreas and the history of our most recent wars and check possible repercussions before you just go 'why not attack a country?'
even at this point, attacking korea 'just like that' is akin to attacking china. no matter how much korea threatens to use its new weapon, that is, technically, a dick move, but without an official declaration of war, not really forbidden
everytime the world threatens NK, NK gets more frantic to finish its nuclear capabilities. because the dear leader banks on it to be the thing that stops the sanctions and such. because you dont just sanction a nation with 'the bomb' and despite the leadership obviously being undemocratic and cruel, its somewhat of an understandable move.
no matter which way, you cant just 'solve' NK.
i mean, you could have proposed to gift them a dummy attack. you know, they fire a missle into the sky, tell their people the us was wiped out and start some secret trade relations on the grounds that the population gets fed and gulags being closed. and in a few decades, this would've all blown over.
what trumps going for right now is so ridiculously transparent, he's trying to bush iraq war his way out of low ratings and he's absolutely accepting NK just annihilating the south and parts of japan in a last glorious display of power. NK with a nuke is no more dangerous than NK without a nuke, at least to the us.
and with hindsight in mind, the whole thing would have required the rest of the world to act as the bigger man years ago, kiss the old mans feet and try to influence the next generation of leader-gods into being better than their parents