United States'policy on Vietnam is examined.

The United States stunbled into a commitment to a shaky government in the 1950s and the unvarying policy of every subsequent administration was to do what was necessary to prevent the collapse of that government. They were doing so not because they anticipated victory but because they saw no alternative . However, high the cost of intervention they believed, the cost of not intervening, of allowing South Vietnam to fall, would be higher. Only when the national and international political situation had shifted to the point where it was possible for American policymakers to reassess the costs of containment- to conclude that the costs of continuing the commitment- was it possible for the United States to begin disengaging.

Please elaborate on this interpretation.
1.How valid is this interpretation?
2. Are there any parts in it that have holes in it?
Some resourses you can use are: America Divided: by Maurice Isserman and Michael Kazin and If I Die In a Combat Zone