This latest missile launch was not unexpected.

South Korean intelligence sources had reported movement of North Korean launch vehicles early last week, while there had been speculation a test would be timed to coincide with a national holiday on 9 September.

Had that happened, it would have been interpreted as a show of strength by Kim Jong Un - a signal, on the anniversary of the country's founding, of where it is heading under his leadership - towards the nuclear deterrent his citizens are told is the only means to secure their survival.

Instead, coming as it does now four days after the UN Security Council passed its strongest sanctions resolution yet, this will now be seen as a statement of North Korea's defiance - a furious rejection of the measures being imposed upon it by the international community.

There may be truth to both, but in trying to interpret the precise message each individual missile is intended to send, we should not lose track of the bigger, crystal clear message the Kim regime is telegraphing over and over again.

Kim is telling us directly where this is heading - he's trying to develop nuclear weapons, capable of reaching the mainland United States, and he is very nearly there.

This is his signature policy. It's known as "Byungjin", and it calls for the simultaneous development of nuclear weapons and the economy.

There is no mystery here, apart from perhaps how the development of the economy is compatible with the pursuit of weapons that bring ever-increasing sanctions, further impoverishing his people.

Presumably that part is intended to come later.

What is less clear is Kim's motive.

The argument North Korean officials make, and several have made to me, is that countries without nuclear weapons are vulnerable to US-led regime change.

They cite the examples of Libya and Iraq, and the fate of Muammar Gaddafi and Saddam Hussein.

Under this rationale, the deterrent - with the ability to threaten the United States directly - is a means to ensure the continued existence of a regime that North Koreans are told is under constant threat from hostile "US imperialist aggressors".

The good news is that if this is the motivation, they would be very unlikely to ever actually use their weapons.

A regime concerned primarily with its own self-preservation would be unlikely to trigger the very conflict that would almost certainly ensure its demise.

The danger comes later, if Kim then believes he has impunity; the US alliance with South Korea and Japan is weakening; and his ability to strike the American homeland would dissuade them from intervening to prevent the reunification of the Korean peninsula by force.

At this stage we cannot know Kim's true intentions - what we do know is that despite the condemnation and the international sanctions, he shows absolutely no sign of voluntarily abandoning his nuclear or missile programmes.

And there will be more launches to come.