PARIS – One of the first things you learn in diplomacy 101 is not to make threats you can’t back up.

But that is just what US Defense Secretary Robert Gates did last week by thundering the US "would not accept," and "would not stand idly by" while North Korea continued to develop nuclear weapons.

North Korea’s nuclear weapons threaten the entire globe, warned Gates, whose own Pentagon has some 10,000 nuclear warheads deployed at home and abroad, 28,500 troops permanently based in South Korea, and large contingents in Japan, Okinawa and Guam.

Not to be out-threatened, North Korea warned back that if attacked, it would turn South Korea’s capitol, Seoul, into "a sea of fire" and bombard Japan.

Dire threats and angry hot air always characterize poisonous relations between isolated, Stalinist North Korea and the US, Japan and South Korea. Their recriminations have become a form of ritualized kabuki theater in which snarls and grimaces replace actual violence.

After much angry posturing, the US, Japan and South Korea usually pay off North Korea’s "Dear Leader," Kim Jong-il, to stop making trouble.

But this time, both Washington and Pyongyang have gone over the top. One wonders how Secretary Gates intends to prevent North Korea from having the nuclear devices it already possesses.

The Pentagon has run out of troops and borrowed money, and is reluctant to tangle with North Korea’s tough, 1.1-million man army. Ever since Vietnam, the US has preferred to use its military only against small nations with limited defense capability, like Grenada, Panama, Somalia, Libya, Afghanistan and Iraq.

There is no way the US will fight a land war against North Korea. A US bombing and missile campaign against North Korea would be unlikely to cripple its nuclear program. But such an attack would certainly trigger a major war.

After North Korea’s second small nuclear test last week, there is real danger this usually harmless kabuki could turn lethal. US and South Korean forces are on high alert and North Korea says it has torn up the cease-fire that supposedly ended the Korean War. US war planes and naval units are buzzing around North Korea like angry hornets.

North Korea’s few nukes are not a world danger – at least not yet. The North has 800 inaccurate medium-ranged missiles aimed at South Korea and Japan, but they only have conventional high explosive warheads. North Korea is not believed to have yet mastered miniaturizing or hardening nuclear warheads for delivery by missile. There are suggestions it may be working on a long-ranged missile.

Pyongyang’s bloodcurdling threats notwithstanding, its infant nuclear force is primarily defensive. North Koreans have had to literally eat grass to pay for their nukes.

When eventually deployed, Kim’s nuclear-armed missiles are designed to deter potential US nuclear strikes on North Korea by threatening counter-strikes on South Korea, Japan and US bases on Okinawa and Guam. North Korea would be unlikely to initiate a nuclear war with a major nuclear power that would result in its immediate obliteration by US nuclear retaliation and vaporization of the Kim dynasty.

But after this week’s nuclear test, a new danger has emerged. The US has renewed threats to stop and search North Korean freighters on the high seas that might be carrying "weapons of mass destruction," missiles or military components to the Mideast. South Korea and Japan will do the same, but only in their coastal waters. North Korea warns, quite correctly, that such a high seas arrest would be an act of war.

The plot thickens. Israel worries that North Korea, desperate for hard cash, will sell more missiles, technology and spare parts to the Arabs or Iran, and in the future, nuclear warheads. Washington frets North Korea may sell a nuclear device to anti-American extremists.

Israel has put intense pressure on the Obama administration to stop any flow of North Korean weapons to the Mideast. The White House responded by threats of a maritime blockade of North Korea.

North Korea says it will retaliate militarily for any high seas seizures, either in its disputed coastal waters against South Korean naval forces, or by attacking US ships and spy aircraft that routinely shadow North Korea’s coast and occasionally overfly North Korea.

If this happens, the US would likely respond by missile strikes and air attacks. North Korea would then riposte with barrages of heavy artillery and long-range rocket batteries along the DMZ against South Korea’s capitol, a mere 25 miles distant. Attacks on US bases in South Korea by North Korea’s large numbers of Scud missiles could follow.

The Obama administration is playing with fire by threatening an act of war against North Korea which has so many American troops in its gun sights.

If Kim Jong-il refuses to back down, Washington will be left with the nasty choice of either taking some sort of military action that is certain to prove indecisive, or lose face with its allies and foes, and listen to Kim crow. That’s the awkward position Secretary Gates has put himself in. What happens when the Dear Leader calls his bluff?

Kim Jong-il is happy to play chicken with Washington because this dangerous game boosts his stature at home and makes him a hero to some Koreans, both North and South, who see Kim as the authentic Korean leader for defying the mighty US and refusing to give in to its threats – a sort of Korean Saddam Hussein. North Korea has long accused South Korea of being an American colony under US military occupation, and North Korea as the only "free, independent Korea."

Like his late father, Kim Il-sung, Kim Jong-il has repeatedly vowed to reunite the Korean Peninsula before he dies. Time is running out for the ailing Kim. His pledge should not be taken lightly. This latest crisis must thus be seen as a function of the inner-Korean struggle for unity – under the Kim dynasty, of course.

The Dear Leader faces internal challenges over plans to name one of his three sons North Korea’s next dynastic leader. The latest nuclear test and America’s threats will help Kim. Another of his foes, South Korea’s conservative, pro-American president, Lee Myung-bak, is now under siege by his own people after the tragic suicide of former president, Roh Moo-hyun, who favored reconciliation with North Korea.

If the North Asian nuclear crisis intensifies, Japan and South Korea may be forced to deploy nuclear weapons which both can do quickly. Japan can produce a nuclear weapon in less than 90 days.

Kim Jong-il has picked his time well. Iraq is heating up again. At least fifty thousand US troops are slated to remain there at least until 2011. The war in Afghanistan and now Pakistan – or Afpak – is going very badly for the US, which is rushing more troops there. Washington has provoked a volcanic upheaval in Pakistan’s Northwest Frontier Province. The US is bankrupt and living on borrowed money. What better time to show who is really boss on the Korean Peninsula.

The Obama administration should proceed with caution. This latest crisis with North Korea is clear proof that America’s world power has already reached its limits.