Got too agree with this, there would be no need for America to use nuclear weapons.
There is of course a huge amount of hysteria in the gutter press putting the shits up those who have less of an understanding of all this. World war 3 and all that.
Here is why nuclear weapons and world war 3 are both unlikely to happen.
China are not greatly impressed by N Korea and most certainly dont want them to have nuclear weapons. If nobody else stops N Korea getting nukes then China would have to. There are maany reasons why China would not allow N Korea to have them. Whilst China will think it not ideal to have the US Military in N Korea this would be over ridden by having some one else sort the problem out. Infact I suspect that amongst other things the Chinese president has probably in effect told Trump if he wants to go in as long as there is no using of nukes and the US fuck off out of it once the job is done then the Chinese will do no more than make the appropriate noises whilst infact being quite relieved that they themselves havent had to sort it.
Russia have no wish to see a nuclear armed N Korea and have no affiliation to them and will take much the same view as China, not too mention Putin will be perfectly happy to see America distracted from Syria and their forces stretched. So Putin wont have an issue with it, again the right political noises and condemnations will be forthcoming.
If Kim has the bottle to conduct a test then I suspect that will be the signal for tin hat time over there. Dependent on North Korea being prepared to retaliate big time in the event of the Yanks hitting them it may be a very spectacular messy but short conflict.
N Korea has a huge army and an awful lot of weapons, but all the kit is obsolete. The US and S Korean air forces would be able to fly virtually unchallenged within hours of any outbreak of hostilities and would take out much of the Norths weaponry within days.
It would be by no means without cost and significant casualties but if they go after North Korea now, and as you say this is the window to do it, more so whilst they may have the secret blessing of China it would probably save a much more difficult problem in ten years time.
I must admit I am beginning to think that this time it is going to kick off royally and I would not be too keen on a holiday to Seoul just now.