Spent most of the past week traveling on business, but between planes, driving and appointments, I kept watching developments on the Korean Peninsula.  Simply stated, tensions in the region are at their highest since the capture of the USS Pueblo in 1968, or the shootdown of a U.S. Navy EC-121 “Warning Star” aircraft fifteen months later.  In both cases, the United States opted against an armed military response, although the Pueblo incident resulted in a large-scale reinforcement of our air assets in Korea, and declassified documents indicate that President Nixon briefly considered a nuclear strike retaliation for the downing of the Navy reconnaissance aircraft.

This time around, our response has been much more measured, for a variety of reasons.  First, Pyongyang’s nuclear arsenal has to be factored into the equation, despite its small size and questionable reliability.  There’s also the matter of the DPRK’s new leader, Kim Jong-un.   No one knows how far Kim will go in pressing his luck, though recent actions affirm that he’s quite willing to push the peninsula to the brink of conflict–and perhaps beyond.  

In recent days, Kim Jong-un has deployed a Musudan intermediate range missile to North Korea’s east coast, in preparation for an upcoming test.  With a range of up to 4,000 km, the Musudan (or BM-25) is capable of hitting U.S. military bases as far away as Guam.  According to The New York Times, South Korean intelligence analysts believe the test could come as early as Wednesday.  In anticipation of an expected launch, the U.S. has beefed up ballistic missile defenses in the Sea of Japan and on Guam.

But there may be limits to any American response.  In the past few hours, the Pentagon has announced plans to postpone a long-scheduled ICBM test from Vandenburg AFB in California, apparently to avoid sending the wrong signal to Pyongyang.  Never mind that such tests have been conducted regularly for the past four decades and the target area (Kwajalein Atoll) is thousands of miles from the Korean peninsual.   The Obama Administration has also been trotting out various officials and spokesmen, who claim the current round of sabre-rattling is nothing new.  Appearing on ABC’s “This Week,” Presidential adviser Dan Pfeiffer said current events are “a pattern of behavior we’ve seen from the North Koreans many times.”

Still, it’s hard to remember a recent crisis on the peninsula that has lasted this long, or escalated to such dangerous levels.  In the past, DPRK nuclear or missile tests were often followed by a cooling off period, as Pyongyang tried to gauge reactions from the region and the United States.  And after that, North Korea officials would offer vague hints about a “deal” (usually involving food aid or a decrease in sanctions) that could repeat similar standoffs in the future.

But Kim Jong-un seems to be operating from a slightly different playbook.  Following nuclear and missile tests late last year, the North Korean leader has steadily ratcheted up tensions with a series of calculated moves, ranging from the “cancellation” of the 1953 armistice that ended the first Korean War, to the public signing of an order authorizing missile units to strike the U.S., and most recently, a warning to embassies that the safety of their personnel could not be guaranteed past 10 April, a date that may coincide with the expected Musudan missile test.

While publicly down-playing the potential threat, the U.S. is making military preparations to deal with various Korean scenarios.  Three American destroyers outfitted for ballistic missile defense are now patrolling the Sea of Japan, along with Japanese ships that have identical capabilities.  The Pentagon also announced plans to send a THAAD battery to Guam in the coming weeks, adding another layer of protection for Andersen Air Force Base and other key facilities on the island.  THAAD’s arrival on Guam will mark the system’s first operational deployment.

Perhaps the week’s most interesting move occurred in China, where thousands of troops were mobilized along the border with North Korea.  Sixty years ago, the People’s Liberation Army surged across the Yalu River to save Kim Il-Sung from defeat.  Virtually no one expects a similar scenario this time around; Beijing is said to be extremely “displeased” with North Korea’s actions, but has done nothing to push its erst-while ally.  The recently observed deployments are probably aimed at preventing thousands of DPRK residents from seeking refuge in China, should war break out on the peninsula.  There have been mobilizations of this type in the past, but the large numbers of troops involved in the PRC drills suggests that China is quite concerned and believes armed conflict is a very distinct possibility.

How could the current situation digress into a shooting war?  At Foreign Policy on-line, Patrick Cronin offers a highly plausible scenario.

Let’s say that the North decides to fire its new mobile KN-08 intermediate-range ballistic missile, capable of reaching U.S. bases in Guam. An X-band radar based in Japan detects the launch, cueing missile defenses aboard Japanese and U.S. ships. The U.S.S. Stetham, an Arleigh Burke-class destroyer equipped with Aegis phased-array radars, fires its SM-3 missiles, which hit and shatter the KN-08 warhead as it begins its final descent. The successful intercept is immediately touted internationally as a victory, but, now desperate for tactical advantage that will allow it to preserve its nuclear and missile programs, the North Korean leadership orders an assault on South Korean patrol vessels and military fortifications built after the 2010 shelling incident.

The regime feels safe in striking out along the maritime boundary because the two sides have repeatedly skirmished in the area in the past 15 years. But President Park, determined to show backbone, dispatches on-alert F-15K fighter aircraft armed with AGM-84E SLAM-Expanded Response air-to-ground missiles to destroy the North Korean installations responsible for the latest assault. For good measure, they also bomb a North Korean mini-submarine pier as belated payback for the sinking of Cheonan. North Korean soldiers and military officers are killed in the attack. Pyongyang vows a merciless response and launches a risky salvo of rockets into downtown Seoul, in hope of shocking the Blue House into seeking an immediate cessation of fighting. But far from ending the tit-for-tat attacks, North Korean actions have now triggered the Second Korean War.   

What happens after that?  A renewed Korean conflict would be both protracted and bloody.  The number killed on both sides would be measured in the tens of thousands–and that assumes we somehow avoid a nuclear exchange.  The early stages of the conflict would be particularly precarious; the planned defense of South Korea is built on blunting the north’s invasion while ROK reserves mobilize and U.S. reinforcements–primarily airpower–rush to the region.  But the bulk of those forces won’t be available until at least 10 days after the war begins.

And did we mention the wave of humanity that will be fleeing Seoul, as DPRK rockets, missiles and artillery rounds rain down on the city?  Many of the city’s 12 million residents will attempt to head south as key ROK reserve try to move north and join the fight.  It’s the kind of gridlock no modern Army has ever encountered.  To give you some idea of the potential congestion problem, a holiday drive from Seoul to Pusan can take up to 24 hours.  Now, picture yourself as a ROK battalion or brigade commander trying to head north against a mass exodus from Seoul.

After the first two weeks, the odds begin to shift against North Korea.  The NKAF won’t be able to protect exposed ground units, and Kim Jong-un’s Army lacks modern, mobile SAMs to hold off Allied airpower.  But that reality is tempered by geography; to “win” the war, Pyongyang only needs to capture Seoul, and inflict enough casualties to compel South Korea and the U.S. to negotiate a new cease-fire–on North Korea’s terms.

Conventional wisdom holds that Kim Jong-un must be persuaded to “climb down” from the geopolitical limb where he is currently perched.  But that assumes that the young dictator is a rational actor (to some degree).  Unfortunately, the evidence to support that contention is inconclusive, at best.  Mr. Kim may genuinely believe that he has enough military power to intimidate the U.S. and its allies, or retake the peninsula by force.

Which brings us back to a component that has been largely missing in this crisis–American leadership. As we’ve noted previously, Defense Secretary Chuck Hagel and Secretary of State John Kerry have issued a number of statements on North Korea, but our Commander-in-Chief has been largely silent.  There is a certain school of thought that American Presidents don’t respond to rhetoric by North Korean dictators, since it tends to elevate their stature.  This is particularly true for Kim Jong-un, who (by some accounts) is still trying to consolidate his hold on power.              

But Mr. Obama’s silence is not playing well in Northeast Asia.  Yesterday, the Japanese announced plans to shoot down any North Korean missile that poses a threat to their territory.  We can assume the statement was coordinated with the U.S., but there was clear frustration in Tokyo.  So far, Washington has made little more than the standard promises about defending its partners, raising new fears that the United States is an unreliable ally.

And that may be the most lasting consequence of the current crisis–assuming it doesn’t boil over into armed conflict.  American reactions to threats from North Korea and China are being closely scrutinized in places like Seoul, Tokyo and Taipei.  There is a growing consensus that U.S. security guarantees only go so far, and democracies in the region may (at some point) have to “go it alone” when it comes to their defense.  Such thinking opens the very real possibility of a new arms race in Northeast Asia, with countries like Japan, South Korea and even Taiwan contemplating development of their own nuclear arsenals.

The cornerstone of President Obama’s global security strategy was his much-heralded “pivot to Asia.”  Now, with the specter of a new Korean War looming on the horizon, many of those affected by that decision are asking if the U.S. position represents a genuine strategy, or just another campaign speech.