North Korea’s fresh round of brinkmanship is poised to throw the U.S. into a double bind: lead a global movement for stronger penalties while reengaging the regime as part of nonproliferation efforts.

The communist country is seen rapidly building its nuclear capabilities. Though it has a long way to go to master the technology for miniaturizing warheads to mount on missiles, Tuesday’s detonation showed sizeable progress, experts say.

For Pyongyang’s ruling clique, a potent atomic arsenal is the sole practical answer to what it calls U.S. hostility. They believe it will only help gain their ends ― being respected as a fellow nuclear power internationally and perhaps having diplomatic relations with Washington.

For U.S. President Barack Obama, North Korea’s aim is precisely the reverse of what his country has championed for more than two decades.

Since the end of the Cold War, the U.S. has been spearheading an arms reduction and nonproliferation campaign, engaging with Russia and sanctioning aspiring nuclear states like Iran as well as terrorist groups.

“It is important for the world to have credibility with respect to our nonproliferation efforts,” Secretary of State John Kerry told reporters in Washington on Wednesday.

“And just as it is impermissible for North Korea to pursue this kind of reckless effort, so we have said it is impermissible with respect to Iran. And what our response is with respect to this will have an impact on all other nonproliferation efforts.”

Kerry called for a “swift, clear, strong and credible response” to Pyongyang’s third nuclear test and its “continued flaunting of its obligations.”

He has been consulting with counterparts in South Korea, China, Japan and Russia to draw up more powerful U.N. measures. Obama also spoke to Japanese Prime Minister Shinzo Abe on Wednesday and South Korean President Lee Myung-bak on Tuesday.

Three weeks into his second term, Obama has yet to hint at a change in his “strategic patience” approach toward North Korea.

In his State of the Union address Tuesday, he called on North Korean leader Kim Jong-un to realize that he would “only achieve security and prosperity by meeting their international obligations.”

Another round of sanctions would almost certainly throw their bilateral relations to a new low. The regime threatened further atomic explosions “if the U.S. complicates the situation.”

Still with the North coming closer to being a nuclear weapons state, Washington will ultimately return to the negotiating table to head off further proliferation and potential exports to its rogue partners, said Koh Yu-hwan, a North Korean studies professor at Dongguk University in Seoul.

“First we should go through the sanctions process. But the U.S. cannot sit idle while North Korea improves its nuclear capability,” he told The Korea Herald.

“The U.S. would have to seek some new solution and reexamine its overall policy on North Korea and the nuclear issue including the six-party denuclearization talks.”

Obama may have relatively more room in maneuvering his policy without reelection pressure, others say.

His top foreign policy and security chiefs ― Kerry and Defense Secretary nominee Chuck Hagel ― have long favored diplomacy in resolving confrontations such as with North Korea and Iran.

A senior official at the Foreign Ministry in Seoul told reporters last week that Obama’s inauguration speech signaling engagement may offer a clue to his policy direction for the next four years.

“We will show the courage to try and resolve our differences with other nations peacefully,” the president said. “Not because we are naive about the dangers we face, but because engagement can more durably lift suspicion and fear.”

The newly brewing nuclear crisis is spurring calls for a shift in the focus of the six-party forum to nonproliferation from denuclearization as a way out of the long-festering standoff.

Many officials and experts have expressed skepticism, saying it may embolden other rogue states and nuclear aspirants and spark an arms race in the region and beyond.

A persistent concern is that the change may undermine policy coordination between Washington and Seoul, given the denuclearization priority enshrined in President-elect Park Geun-hye’s signature “trust-building” process policy.

Hwang Ji-hwan, a North Korean studies professor at Myongji University in Seoul, pointed out the conceptual difference between Seoul’s denuclearization aim focusing on the peninsula and Washington’s nonproliferation initiative as a world vision.

“But if the U.S. swings to nonproliferation (for North Korea), though it’s unlikely, it will be a huge hurdle for our North Korea and unification policy because we will have to change the whole external and defense framework,” he added.

Washington needs to embrace Beijing in its broader regional strategy to break the impasse with Pyongyang, according to Hong Hyun-ik, a senior researcher at the private Sejong Institute.

Threatened by the U.S.’ refocusing toward Asia, China may now be even more reluctant to lend a hand in persuading the wayward regime to change course.

“The U.S. should adjust its East Asia strategy first if it wants China to sincerely press North Korea and stop its nuclear development.” he said.

“So long as the U.S. piles strategic pressure on China, China will continue to consider North Korea to be a friendly partner. They should come up with a scheme in which they can build peace together.”

By Shin Hyon-hee (heeshin@heraldcorp.com)