The flaws in Donald Trump's approach to North Korea

When Donald Trump first delivered his "fire and fury" threat, there was some suggestion that perhaps this was a one-off - an ad-hoc remark from a President who likes to depart from the script.

But this is starting to look like a strategy.

Presented with the opportunity to walk back, or at least to qualify, his earlier remarks, Mr Trump instead underlined them - warning Pyongyang to "be very very nervous," and that maybe he hadn't been tough enough

Presumably the intention is to intimidate Kim Jong Un into submission, or at least to not conduct any more missile tests, while telegraphing to China that the US is prepared to take military action, with the catastrophic regional consequences that would bring, unless they rein their sometime ally in.

There are a couple of significant problems with this approach.

Firstly, China's leadership doesn't see this as their problem - their officials consistently call on all sides to exercise restraint, while proposing their own "dual freeze" initiative - where the US and South Korea suspend military exercises in return for a freeze of the North's nuclear and missile programmes.