To be sure, the corrosive Vietnam syndrome seems to particularly trouble Democratic administrations. It was after all during the tenure of two Democrats, John F. Kennedy and Lyndon Johnson, that the United States deepened its commitment to the Southeast Asian quagmire, discrediting American power, and scuttling a promising domestic reform agenda. As the Obama team focuses on health care and climate change, liberals once more fear that a distant conflict could engulf another promising presidency. To preserve the liberal hour they seek to avoid the liberal nightmare.

The Vietnamese success against an august superpower was indeed a remarkable achievement. However, it was an accomplishment that came about due to a fortuitous confluence of reasons: Hanoi’s nationalistic credibility, its careful exploitation of the advantages of the Cold War, and a particularly arrogant and incompetent American military command.

The Hanoi leadership’s ability to fuse communism with nationalism stood in contrast to America’s South Vietnamese allies whose corrupt indulgences and lack of popular appeal made them a terrible contrast. General William Westmoreland’s strategy of attrition where he hoped that somehow US forces would outlast the enemy on its home terrain only contributed to Washington’s dilemma.

Despite all these shortcomings, the United States may still have prevailed if the Soviet Union and China had not sustained North Vietnam’s war effort through generous material assistance while deterring America from attacking and occupying their enterprising ally. In the end, the Vietnam War was too complicated and its legacy too divisive to serve as a cautionary tale for 21st century US foreign policy.

All this is not to suggest that the Obama administration should dispatch more troops to Afghanistan. The notion that Afghanistan is central to United States national security is at best a dubious proposition given the ability of Al Qaeda terrorist cells to mutate in a variety of other locations.

Afghanistan’s history militates against easy solutions imposed by foreigners. A country known for its tribal fragmentations, absence of credible central authority, and fiercely independent population is hardly an ideal place for America’s nation-building schemes. To this complicated matrix one has to add a lack of allied support and a disastrous presidential election that further eroded government legitimacy.

In the end, General Stanley McChrystal’s ambitious strategy of securing the countryside may require a larger contingent of troops without producing tangible results. A scaled back US presence focused on controlling key strategic sectors and eliminating terrorist sanctuaries may better address US concerns. Such a campaign removes the false choice between counter-insurgency and counter-terrorism and concentrates on core objectives.

For too long, the haunting specter of the Vietnam has had a debilitating impact on leading Democrats. The fear of entanglement in foreign wars has led many to instinctively oppose the use of force. The central lesson of Vietnam ought to be that the civilian leadership must ask probing questions before committing troops. And that the advice of the military brass cannot be the sole guide of US policy irrespective of concerns of commanders on the ground. In this sense, an administration that has been accused of dithering seems to have learned some of the right lessons of Vietnam.

Ray Takeyh is a senior fellow at the Council on Foreign Relations.