Sabre rattling

North Korea's state media reported on Tuesday that there were plans to restart a nuclear reactor at the Yongbyon complex to enable production of weapons-grade plutonium to be resumed.

The reactor was closed in 2007 as the result of international six-party talks to end North Korea's nuclear weapons program - the talks have been stalled since 2009.

Pyongyang has also announced it will restart the uranium enrichment plant at the complex.

Washington has reacted to the latest provocation from Pyongyang with concern. It has disagreed with all of North Korea's leaders over the past two decades.

In 1994, US President Bill Clinton made a deal with North Korean leader Kim Il Sung: North Korea would freeze its nuclear weapons development program in return for two light water reactors. In 2002, President George W. Bush included North Korea in his "Axis of Evil" and slapped sanctions against Kim Jong Il's regime.

In 2003, with China playing a mediating role, he agreed to the six-party talks to bring North Korea's nuclear program under control.

His successor President Barack Obama has had to deal with Kim Jong Un. His belief has tended to be that North Korea will be forced to give up its program if there is enough pressure and incentive.

Pyongyang fed this hope for some time but seems to have changed strategy.

A nuclear-armed nation

After Kim Jong Il's death in December 2011, North Korea proclaimed its position as a nuclear-armed nation in its new constitution.

The Central Committee of the Workers' Party of Korea decided that the state's arsenal of nuclear weapons would be expanded both in terms of quantity and quality and that it would not be abandoned "so long as imperialists and nuclear threats" existed in this world. It said that nuclear weapons were not negotiatiable - not even against "billions of dollars."

There are two more reasons why North Korea won't give up the bomb. For the army, on whose bayonets rest the Kim family's power, nuclear weapons are a satisfactory substitute for better quality conventional weapons that North Korea cannot afford to buy. Secondly, patriotism can be boosted through North Korea's rise to nuclear power.

On par with each other

North Korea's leaders are clinging on to the atom bomb as the ultimate shield against "regime change." Their opinion has been reinforced by the example of Saddam Hussein who did not have nuclear weapons and lost his power in a US invasion, and of Moammar Gadhafi, whose fall was caused by what Pyongyang calls a US-backed insurgency. "Nuclear armed forces represent the nation's life," Kim Jong Un declared at the end of March.

This recent saber-rattling is intended to force the US into bilateral negotiations over a peace treaty 60 years after the end of the Korean War. Pyongyang wants to be on a par with Washington, for one atomic power to negotiate with another.

Its scrapping of the ceasefire agreement and non-aggression pact with South Korea is intended to state to the US that Pyongyang is moving away from diplomatic and rhetorical exchange and is now treating its relations with Seoul as if they were in a state of war.

US sticks to containment policy

Washington is not succumbing to the threats and is maintaining its old strategy: Tougher sanctions and demonstrations of military power are intended to force Pyongyang back to the negotiating table. Obama has said he does not believe that Kim Jong Un intends to start a war.

The US is counting on China's support and hoping that Beijing will do everything it can to prevent any military skirmishes.

At the same time the US and its ally South Korea have also escalated the situation somewhat. The visible deployment of two nuclear-capable stealth bombers during recent maneuvers in South Korea recalled the traumas of the 1950-53 Korean War.

General Douglas MacArthur spread fear by letting long-range bombers fly at a low altitude and thus suggesting that an atomic bomb could be dropped.

By making this demonstration of nuclear power, President Obama has thus boosted Kim Jong Un's argument that Washington wants to instigate a nuclear war.

North Korea's response is another sign that Clinton, Bush and Obama have all failed to take the bomb away from Pyongyang.