US and S. Korea strive for unity amid fears of a of N. Korean nuke test

The United States and South Korea are trying to work through their differences in hopes of steering North Korea away from conducting a possible underground nuclear test.

While intelligence estimates suggest that the North may possess six or more nuclear warheads, a test would confer on the North the clout of a full-fledged member of the nuclear club. It also could trigger a nuclear arms race among regional powers, particularly Japan and Taiwan, both of which are believed to have the technology for producing nuclear weapons, as well as China, already a nuclear power.

South Korea is adopting what Foreign Minister Ban Ki Moon says are "concrete" – if unspecified – measures both to counteract the threat and to persuade North Korea of the dangers of provoking a regional crisis. Mr. Ban, however, is equally interested in persuading the senior US diplomat for the region, Christopher Hill, from exacerbating tensions as he touches down in Tokyo, Beijing, and Seoul in an effort to bring unified pressure on North Korea.

The US is pressing for a strict interpretation of the UN Security Council resolution banning any dealings with the North that might support its arms trade. Such a reading would deepen the economic damage done to the regime by US Treasury Department efforts to curb international trade with North Korea.

The concern is that North Korean leader Kim Jong Il will conclude he has no choice but to fight in order to survive, much "like a rat driven into a corner" – a phrase widely used among South Koreans. Or, as Ban put it, North Korea will find itself "at dead end with no way out."

The different approaches to the nuclear standoff are part of a rift between President Bush and South Korean President Roh Moo-hyun, who has long pursued a soft-line policy of reconciliation with the North. As the two leaders prepare to meet next week in Washington, regional analysts are concerned that North Korea may see an opportunity to deepen the wedge between the allies.

If Kim Jong Il does not press the trigger on an underground nuclear test, he may well order another test-firing of missiles reminiscent of the July launch of seven missiles.

"I had expected North Korea would fire more missiles," says Mark Fitzpatrick, senior fellow for nonproliferation at the International Institute for Strategic Studies in London. "Undoubtedly North Korea has more tests it would like to do" – particularly since the long-range Taepodong 2, potentially the most fearsome of all the missiles in North Korea's arsenal, fizzled into the sea 42 seconds after lifting off on July 4.

As for a nuclear test, Mr. Fitzpatrick says "signs of a potential test are worrisome."

"North Korea has demonstrated a willingness to disregard the advice of its only ally, China," which is trying to persuade Mr. Kim to lower the level of confrontation by inviting him to Beijing for more talks on economic aid and trade, Fitzpatrick says.

While the North Korean regime does not want to be seen as yielding to Chinese pressure, he adds, a nuclear test "is their last card and I do not see any reason for them to do it now."

Rather, he says, Kim may have accomplished a tactical aim by "demonstrating a willingness to test" without doing so.

South Korean conservatives have warned President Roh against any action that might jeopardize the US-Korean alliance. They are especially concerned about plans for placing South Korean troops under South Korean command – rather than a unified, US-led command – in case of war.

The US and South Korea, though, may come to terms in that debate. Roh, whose popularity has plummeted in recent months, has said he has no intention of jettisoning the alliance, while Bush has said South Korean forces are strong enough to defend the South.

Still, US conservatives, like those in South Korea, fear damage to the alliance.

"I worry about the differences of opinion between Korean and American government officials," Edwin Feulner, head of the Heritage Foundation, remarked recently in Seoul. "If North Korea continues on its current tread line," he warned, governments in the region "will have no choice but to counter North Korea."