No easy recipe

DENUCLEARISATION? It is a big word, and so is the challenge facing President Trump as he heads towards a summit with Kim Jong-un centred on reducing or eliminating the threat of North Korea’s nuclear weapons and missile systems.

There’s no easy, snap-your-fingers recipe, and there are big traps. How do we know? Because it was tried after the collapse of the Soviet Union, which produced a host of good lessons.

A summit that results in headline-grabbing commitments may be a first and necessary step. But agreements will have no meaning if they don’t lead to verifiable and lasting results.

Denuclearisation is complex and demands a whole chain of actions and co-operation between suspicious and hostile actors.

The point is not to give North Korea endless time. But reversing an arms build-up is a serious industrial headache.

It is fantasy to think that the North’s nuclear weapons can just be loaded onto a cargo plane and flown away. They need to be dismantled with help from the people who built them.

The Cold War clean-up shows that full disclosure is critical. Mr Trump must demand that North Korea come clean about all its nuclear programmes, as well as chemical and biological weapons research and development.