A few points in particular seem stretches of logic (or merely circumventions of logic...).
"...North Korea's potential for anarchy is equal to that of Iraq..."
This seems to miss a fundamental difference between the social make-up of Iraq and that of North Korea. Kaplan presages the comment with a reference to the potential for "widespread lawlessness" compounded by "guerilla mentality" of the armed forces and the flow of refuges should the regime fall. But this is a far cry from the situation in Iraq. While North Korea does intend to rely on guerilla tactics should there be a military conflict (and the North Korean bunker system will make Hezbollah’s southern Lebanon bunkers look like holes dug by kids in the sandbox), the "anarchy" in Iraq is not due to the guerilla nature of the former Baathists per say, but to the ethnic and religious divisions and the historical animosities among these factions due to years of minority Sunni domination over the Shia and Kurds. Even within these warring ethnic and sectarian forces there are varying competing factions, and the imposed outside influences of the United States, Saudi Arabia, Iran and Turkey. But North Korea's relatively homogenous society does not have the ethnic or religious fault lines (though there are fault lines among the varying degrees of political "reliability" and between the various economic levels). But fundamentally, Iraq is riven by deeper divisions than North Korea, and well there may be chaos, it will not be along the lines of the Iraqi internal conflicts.
"The United States has a history of underestimating historical-ethnic disputes: in the 1980s, it paid insufficient attention to ethnic tensions in Yugoslavia; more recently, it downplayed Sunni-Shiite tensions in Iraq. It should not make the same mistake in Asia."
This comment is in relation to the potential for war between a reunified Korea and Japan. Now first, there is here, in the reference to the Shia-Sunni split, a recognition that the earlier comparison of North Korea to Iraq is misleading at best. But aside from that, while I agree there will be higher tensions and even the possibility of war between a unified Korea and Japan, there are clear geographical differences between the examples – Yugoslavia and Iraq – and the Korea-Japan dynamic. First and foremost, in the cases of Yugoslavia and Iraq, there is a shared geographical space for competing ethnic and sectarian groups. In the Korea-Japan dynamic, the two occupy distinct geographical spaces, and while there is the dispute over Tokdo, the islet is far from either shore. Iraqi and Yugoslav conflicts were the result of centuries of frictions between competing interests vying for the same space, of groups liberated from an oppressive power, seeking revenge for perceived (or real) injustices of the past, all on territory they both claimed. A better example would be if the reunified Germany attacked France or Poland – or the Soviet Union. As is, the current comparison misuses common examples and ignores geopolitical realities of the territories in question to raise the specter of a conflict that may be possible, but is not comparable to the examples.
And yes, this may all be picking nits, but what else am I to do in my free time. And more importantly, if one wants to make an argument for trouble should North Korea collapse, there are many solid trains of logic that can be followed, rather than making simple and inaccurate comparisons in a manner that would garner poor grades in a history or poli-sci class.
The fear of the "Korean left" is also rather overblown and misrepresented, but perfectly mirrors the words of those behind the high walls of Yongsan garrison. In a potential war scenario, Kaplan suggests the "South Korean left – which has been made powerful by an intrusively large American troop presence and by decades of manipulation by the North" would join with the "the United Nations and the global media" to blame the United States for attacking North Korea, and thereby halt any military action and prop up North Korea with economic rewards. This is one of those "Team America" scenarios, where liberal media, intentionally or not, cooperates with North Korea's plans. But the reference to the South Korean left is particularly interesting, as it is a very shallow and misleading read of the "anti-Americanism" and "leftism" in South Korea. The core of the "left leaning" tendencies in South Korea are neither caused by the U.S. military presence or the machinations of the puppet-master Kim Jong Il, but do to the traditional nature of Korea. After the Japanese were booted in 1945, much of South Korea was heading Left as fast as the North. It fit the formerly agrarian repressed society quite well. But even the North’s "left" was and is always more "Korean" than "Communist." But this topic could take chapters to further expound on, and would also need to address why the South Korean left never fulfilled Pyongyang's expectations with a rising in 1950.
Overall, though, what got me about the Kaplan article was the sheer disdain it exudes toward both North and South Korea, and even toward the very peninsula on which the divided nation sits. From the initial smug use of "KFR" (Kim Family Regime) to refer to North Korea to parenthetical (and gratuitous) comment that the tallest Korean soldiers on both sides of the line in Panmunjom are "short by American standards" to the criticism of the "lousy" weather on the Peninsula. It all read as if Kaplan, or those he interviewed, simply expressed all the worst stereotypes of life in Korea as seen from someone intentionally isolated, unwilling to be there, and generally ornery at all things not whatever state they were originally from. This outside disdain, this sense that the unfamiliar is automatically inferior, that alternative viewpoints and perspectives, cultural norms of a different color, are automatically sub-standard, is what convinces people around the world that Americans are smug idiots. As was once told to an aspiring Spiderman – with great power comes great responsibility. The United States is a great power, not only is size and strength, but in underlying ideals, morals and social structures. But there is a responsibility not to simply let that power turn into a bludgeon, not to let that sense of power blind one to the fact that there are differing perspectives that may be just as "right" ... at least from the interests and background of the people involved. South Korea has different views of the strategic landscape. So does North Korea. That is natural. The United States has its own views, and that is natural. These views come into conflict, and each side will do what they see best to maintain their own views. That is natural. If their views are different, they are our enemy. If they match, they are our ally. But underestimating them by heaping disdain on their views, motivations or perceived weaknesses will be what truly leads the United States into trouble.