The US should try to dispel China's concern about potential negative effects on its national interests in the event of North Korea's collapse in order to win Beijing's help in pressuring Pyongyang to give up its nuclear programs, a US expert said.

Richard Haass, president of the Council on Foreign Relations, also said in an article that should such persuasive efforts toward China fail, the US would have to either live with a North Korea capable of striking the US with nuclear missiles or launch military action to take out the North's nuclear and missile facilities.

Haass said that neither negotiations nor sanctions appear to be a solution to the problem, saying Pyongyang is unlikely to give up what it considers to be its best guarantee of survival and sanctions won't work as long as China is supportive of the North.

"As a result, it makes more sense to focus on diplomacy with China. The US, after consulting closely with South Korea and Japan, should meet with Chinese officials to discuss what a unified Korea would look like, so that some Chinese concerns could be met," he said in the article posted on the think tank's website.

"For example, a unified country could be non-nuclear, and any US military forces that remained on the Peninsula could be fewer and farther south than they are now," he said.

China is North Korea's last-remaining major ally and a key provider of food and fuel supplies. But it has been reluctant to use its influence over Pyongyang for fears that pushing the regime too hard could result in instability in the North and hurt Chinese national interests.

Analysts say that China often increased pressure on the North in the past, too, especially when Pyongyang defied international appeals and carried out nuclear tests and other provocative acts, but China never went as far as to cause real pain to the North.

Haass said that it is possible US efforts to persuade China won't lead to any meaningful diminution in Chinese support for North Korea. In that case, the US would have three more options, he said.

"One would be to live with a North Korea in possession of missiles that could bring nuclear bombs to US soil," he said. "The policy would become one of defense (deploying additional anti-missile systems) and deterrence, with North Korea understanding that any use or spread of nuclear weapons would lead to the end of the regime and possibly nuclear retaliation."

The second option would be a military attack on the North's nuclear and missile capabilities, he said.

"The danger is that such a strike might not achieve all of its objectives and trigger either a conventional military attack on South Korea (where nearly 30,000 US troops are based) or even a nuclear attack from the North," he said.

The third option would be to launch such a conventional military attack only if intelligence showed North Korea was putting its missiles on alert and readying them for imminent use, but the danger in that option is the intelligence might not be sufficiently clear or come early enough, he said.

"If much is unknown, what seems all but certain is that whoever wins November's US presidential election will confront a fateful decision regarding North Korea sometime during her or his term," the expert said. (Yonhap)