"It was always a bad year to get out of Vietnam"
Obama’s Vietnam: “Vietnam analogies can be tiresome. To critics, especially those on the left, all American interventions after Vietnam have been potential “quagmires.” But sometimes clichés come true, and, especially lately, it seems that the war in Afghanistan is shaping up in all-too-familiar ways. The parallels are disturbing: the president, eager to show his toughness, vows to do what it takes to “win.” The nation that we are supposedly rescuing is no nation at all but rather a deeply divided, semi-failed state with an incompetent, corrupt government held to be illegitimate by a large portion of its population. The enemy is well accustomed to resisting foreign invaders and can escape into convenient refuges across the border. There are constraints on America striking those sanctuaries. Meanwhile, neighboring countries may see a chance to bog America down in a costly war. Last, there is no easy way out.” (From January 2009)
And,
Winning the Good War: “The growing skepticism about Obama’s chances for success in Afghanistan is largely based on deep misreadings of both the country’s history and the views of its people, which are often compounded by facile comparisons to the United States’s misadventures of past decades in Southeast Asia and the Middle East. Afghanistan will not be Obama’s Vietnam, nor will it be his Iraq. Rather, the renewed and better resourced American effort in Afghanistan will, in time, produce a relatively stable and prosperous Central Asian state.” (From July 2009)
I don’t know who’s right, but they’re interesting reads and worth keeping both in mind as Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, bounds around Pakistan to discuss the threat from that country’s takfiri militants. Because that fight there is going to have a large bearing on the fight in Afghanistan.

I personally prefer not to compare one insurgency to another, especially when they’re in two such different parts of the world. In Vietnam there was one dominant ethnic group (albeit with other groups that were involved in the fighting), one main resistance front, and the population seems to have suffered more under the Southern regime than under guerrilla authority. To contrast in Afghanistan, there are many different ethnic groups all of whom are capable of destabilizing the region, multiple different factions (though I admit that the Taleban and related groups appear to be the strongest and most unified), and the population did not really prosper after the Taleban took most of the nation. In fact it seems to be quite the opposite with things getting worse. That doesn’t mean that we can’t learn anything about counterinsurgency from Vietnam, but an honest analyst would be hesitant to take that route too far.