From the Collins mission and Diem's successful response to the sect crisis in April and May 1955 to the end of the Eisenhower presidency, Vietnam was not a primary concern to U.S. policy makers, who focused their attentions instead on areas of greater importance such as Europe, Japan, China, and the Middle East. Nevertheless, after the Geneva partition of Vietnam, the creation of SEATO, and the establishment of a U.S. Army training mission to Vietnam, the American commitment to Diem was unmistakable and irrevocable. As a result, America's military leaders began to take a more optimistic approach to affairs in Vietnam, apparently reversing their earlier views about the dangers of war in Indochina.

These appearances were somewhat deceptive, however; the change in military thinking was not as profound as it seems at first glance. To be sure, the new MAAG commander, General Samuel Williams, was as optimistic and deaf to criticism as his predecessor, O'Daniel, had been. Williams ignored both Diem's repressive ways and the need to train the southern Vietnamese army to fight a guerrilla war. With U.S. acquiescence, Diem organized his army not to fight the Communist enemy so much as to maintain his own authority. Other military leaders, however, continued to debate military policy in Vietnam.