SEOUL — In a farewell speech to the nation six days before leaving office, South Korean President Lee Myung-bak on Tuesday warned Pyongyang its missiles and weapons are taking the North “closer and closer to a dead-end.”

Lee alerted his compatriots to hastily prepare for reunification of the Korean peninsula. The president asserted that “even though the North Korean regime is refusing to change, its citizens are quickly changing and nobody can block that.

However, there is no outside evidence of any citizen protests in isolated North Korea which human rights advocates describe as one of the world’s most repressive states.

In past months, North Korea has defied international sanctions by launching a rocket into orbit and claiming a successful underground test of a third nuclear device.

Negotiations are underway in New York, with Chinese and American diplomats seen as the key players, for a fresh round of U.N. sanctions to be imposed on North Korea.

Frustration about Pyongyang’s continued defiance of existing U.N. resolutions barring it from ballistic missile and nuclear weapons development is evident at a two-day gathering of 200 nuclear scientists, engineers, policy analysts and public intellectuals from around the world underway in Seoul

North Korea dominates the agenda at the Asan 2013 Nuclear Forum where participants are in disagreement about to blame for the perceived diplomatic failures and what to do next.

“North Korea is not afraid of sanctions” because it has no middle class to appease, said Vasily Mikheev, vice president of the Institute of World Economy and International Relations at the Russian Academy of Sciences.

Japan Institute of International Affairs adjunct fellow Tetsuya Endo, formerly Japan’s ambassador tasked with normalization talks with North Korea, spoke on the same panel titled “Dealing with a Nuclear North Korea.” He predicted it is “only a matter of time” before Pyongyang’s scientists miniaturize a nuclear weapon that could be placed atop a long-range rocket.

But a former U.S. policy maker, Joel Wit, declared that “none of us here can predict the future of North Korea’s intentions.”

Wit says it is also important to dispel the myths that North Korea is isolated, failing or run by crazy leaders.

“They are not crazy. They are realists about maneuvering among great powers,” said Wit, the senior research scholar of the US-Korea Institute at the Johns Hopkins School of Advanced International Studies.

Wit, a former U.S. State Department official who worked extensively on nuclear arms control and North Korea issues, added that Pyongyang’s recent actions require Washington to “re-examine its current approach of weak sanctions and weak diplomacy.”

All of Washington’s options regarding North Korea are “very difficult,” according to Gary Samore who coordinated the attempt to control weapons of mass destruction in the first term of the Obama administration.

“Using military force is not attractive because that could trigger a broader conflict on the Korean peninsula. Sanctions are hard to impose because North Korea is isolated and China protects North Korea,“ said Samore. “Our experience with diplomacy with North Korea is a very unhappy experience because they cheated or reneged on every agreement they reached.”

Chung Mong-joon, the Asan Institute’s patron and honorary chairman, best known as a billionaire lawmaker from the governing Saenuri Party, noted in opening remarks that his country “needs to think the unthinkable.” And, that scenario, Chung warned, may mean South Korea having its own nuclear arsenal as “the only way to negotiate a grand bargain with North Korea.”

Chung characterized the protection provided by the United States with its nuclear force as a “torn umbrella” in need of repair.

South Korean reporters are pestering forum attendees for responses to statements by Chung and other prominent South Koreans that Seoul needs its own nuclear weapons or should ask Washington to re-deploy tactical nuclear weapons on the peninsula.

“U.S. nuclear weapons are not needed in South Korea from a military perspective and the country building its own nuclear bomb would be an even worse choice,” said MacArthur Foundation President Robert Gallucci.

“That would be a grievous mistake,” said Gallucci to reporters. “It’s a decision, of course, that South Korea, now a treaty adherent to the Nuclear Non-Proliferation Treaty, would have to make in its own sovereign interests. And, my view is that those interests would not justify the acquisition of nuclear weapons.”

The consequences of a step in that direction, he predicted, would “be serious and negative for South Korea and other states in the region.”

Gallucci, as a diplomat in 1994, negotiated a deal with Pyongyang on nuclear reactors intended to avoid a confrontation between the United States and North Korea.

Many analysts assert Beijing’s cooperation is critical to resolving the current crisis.

China could cripple North Korea’s meager, but desperately needed, international commerce and its related financial transactions. It has expressed increasing frustration with Pyongyang’s recent provocation.

But Chinese analysts say their government has no desire to suffocate North Korea to the point of collapse. That would create a humanitarian crisis on China’s border and the prospect of a unified Korea allied with the United States.

The two Koreas fought a devastating three-year war to a stalemate in 1953. The United States led U.N. forces formed to save South Korea after the North invaded in 1950. China intervened to aid the North Koreans.

South Korea was not a signatory to the armistice and the two Koreas have never normalized relations, as both still claim the entire peninsula and they technically remain at war.