From The INternational Herald Tribune:

Within days of the last Marine helicopter lifting off from the American Embassy in Saigon on April 30, one could see a new regional power balance taking shape.

It was a very different order from the one that the Kennedy administration had feared when it committed troops to Vietnam more than a decade earlier. Instead of triggering the fall of Southeast Asian dominoes into China’s lap, Vietnam was emerging as a barrier against the very influence that Washington had fought – Beijing’s.