North Korea and its nuclear weapons program simply won't go away on its own, and neither will the strategic, fundamental differences of view and approach to dealing with that problem, which are eating away at the alliance.

"The differences over North Korea are the source of the problem (between the two countries). Everything else -- anti-Americanism, disputes over troop levels -- are all precisely the symptoms of the real problem, which is the fundamentally different view of North Korea," said a Korea expert who requested anonymity.

The difference is the perception of what underpins North Korea's danger to peace and stability, which is heightened by its nuclear weapons program. To the United States, Japan and others, it's Pyongyang's confrontational bent, disregard for international rules and mandates, weapons proliferation activities, militarism and dictatorship. To 21st century South Koreans, the North is a threat not a threat because of its military strength per se, but because of its societal weaknesses -- a primitive economy, hunger and isolation.

The United States wants Pyongyang and its nuclear program brought to heel through tough economic sanctions if it refuses to return to international negotiations with an honest commitment to resolving the issue. South Korea believes carrots and outreach should trump actions that may cause the North to remain recalcitrant and thus continue in its economic peril.

Although neither Bush nor Roh spoke directly about their differences when they met with reporters following their initial session, it was in the subtext of remarks.

"As for the question about the common and broad approach being talked about between our two countries for the re-start of the six-party talks, I must tell you that we are at the working level of consulting very closely on this issue, but we have not yet reached a conclusion and this issue is very complex," Roh told reporters at the White House.

"What is important to remember is the fact that we are consulting closely on the North Korea nuclear issue and we are consulting on ways to re-start the six-party process, and I believe this is the important point."

The six-party talks involve North Korea, South Korea, Russia, China, Japan and the United States. North Korea has boycotted the talks for nearly a year, citing U.S. hostility.

One sign of that hostility was a move that caused a number of international banks to cease doing business with North Korea amid allegations of its involvement in the counterfeiting of U.S. dollars.

In July, North Korea deepened the divide by test-firing more than a dozen missiles in defiance of international opinion. Some of the missiles were theoretically capable of hitting Japan, and one could have theoretically struck the western United States. U.S. intelligence sources were quoted recently as saying they believed North Korea could now be planning a nuclear test, something which has set off alarm bells in world capitals.

The two factors have played an important role in the strengthening of cooperation between Japan and the United States in ballistic missile defense.

South Korea joined in the international condemnation of the North Korean missile tests, but is still reluctant to push for deep international sanctions. It has also publicly downplayed the possibility of nuclear testing by the North.

The nuclear stand-off was sparked by North Korea's surreptitious resumption of nuclear fuel enrichment activities after having signed an agreement with the Clinton administration to stop them in return for aid.

In 2002, a U.S. official informed North Korea the United States was aware of the violation, which North Korea then admitted.

In 2003, North Korea admitted what had been strongly suspected for years -- it actually possessed nuclear weaponry. The number of weapons, however, has never been determined.

North Korea and Iran are seen in Washington as the two largest weapons proliferation threats. In its dealings with both, the Bush administration has taken pains to emphasize it is committed to a diplomatic approach.

There is no disagreement between Washington and Seoul on the need for diplomacy. The argument, which won't go away, is the tools to be used in that diplomatic effort.

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