SEOUL: The UN Security Council has been here before... several times: debating how to punish North Korea for -- as Pyongyang would have it -- reacting to the last time it got punished.

North Korea flagged its February 12 nuclear test three weeks in advance in an official statement released by the National Defence Commission, the country's top military body.

But the countdown really began two months ago when the North launched a long-range rocket and set in motion a now-familiar chain of events that was always going to end in an underground chamber at the Punggye-ri nuclear test site.

The international community condemned the launch and the UN imposed sanctions, which North Korea then used as justification for conducting an atomic test.

An almost identical pattern was followed for the North's two previous nuclear tests in 2006 and 2009.

The UN Security Council is certain to impose fresh or tightened sanctions on Pyongyang after the latest test, but most experts agree that the sanctions route -- until now -- has been largely ineffective.

"Getting unanimous Security Council consensus on another resolution doesn't even send a signal anymore if we are designating North Korean entities or individuals that cannot be effectively sanctioned," said US academic and researcher Stephan Haggard.

"Indeed, it is worse: ritualised UN action is corrosive of our credibility because it continually paints red lines that we are forced to repaint," Haggard said.

The option of significantly upping the sanctions ante with wider and more punitive measures -- especially on financial institutions dealing with North Korea -- is restricted by China.

As Pyongyang's sole major ally and economic benefactor, China has always sheltered the North from the tough measures the United States would like to see the UN impose.

While Beijing's patience with its recalcitrant neighbour is clearly wearing very thin, it is not about to support any action that might put the North in danger of collapse.

Most analysts, therefore, argue for a strategic re-think that throws out the old North Korea playbook and looks for a realistic long-term solution.

For some, like Andrei Lankov, a North Korean expert at Kookmin University in Seoul, this means accepting the unpalatable truth that North Korea cannot be prevented from becoming a fully-fledged nuclear weapons state.

"The pipe dream of denuclearisation should be discarded; arms control is the only attainable goal," said Lankov.

"The aim should be to reach an arms control agreement which implicitly accepts North Korea's claim to being a nuclear power, while also limiting the size of its nuclear arsenal," Lankov said.

But North Korea has a long record of reneging on agreements, as Lankov himself admits, and such an approach would be vulnerable to accusations of appeasement, especially in US and South Korean domestic political circles.

One of the main challenges of North Korea's historical use of brinkmanship to earn concessions, is that it makes engagement with Pyongyang seem less like realpolitik and more like reward for provocation.

David Albright, president of the Institute for Science and International Security, believes a "new formulation" is necessary to break the provocation-engagement cycle.

"A strategy of engagement that does not reward the test but seeks to moderate the regime's behaviour through sustained dialogue may be most productive going forward," Albright said.

Before the North's rocket launch in December, 2013 had looked like a year full of opportunity for such a dialogue and resurrecting the six-party talks with the two Koreas, China, Japan, Russia and the United States.

South Korea, China and Japan were undergoing leadership transitions, while US President Barack Obama was about to start his second term.

Many felt this offered the chance of a fresh start with Pyongyang, working off a blank slate, with new faces and renewed energy.

But the rocket launch and then the nuclear test have made resuming any sort of meaningful dialogue all but impossible -- at least in the short term.

For South Korean president-elect Park Geun-Hye, who takes office in a week, campaign promises of greater engagement with Pyongyang will now have to be shelved for fear of inciting the hawks in her conservative party.

In the meantime, some analysts suggest the best way forward is to ignore Pyongyang completely for a while, and focus instead on building a consensus between the main outside players.

"There are signs that China is listening more to US concerns about North Korea's nuclear provocation," said Albright.

"The goal must be the United States developing common positions with China, along with South Korea and Japan, making it harder for North Korea to play China against the United States," he added.