Final answer:
The escalation of the Vietnam War post-Gulf of Tonkin incident was influenced by a mix of the first attack's confirmation, doubts about the second attack, and political calculations around U.S. resolve and containment policy.
Step-by-step explanation:
The decision to escalate the war in Vietnam, particularly following the Gulf of Tonkin incident, was based on a combination of factors. The initial attack on August 2nd on the USS Maddox was confirmed, but the second alleged attack on August 4th, which involved the USS Maddox and the USS Turner Joy, was later doubted by officials, including President Johnson. Despite these doubts, the Johnson administration used the incident to secure the Gulf of Tonkin Resolution from Congress, which granted the President authority to increase U.S. military involvement in Vietnam without a formal declaration of war. This decision was also influenced by political calculations and concerns about the United States' image and containment policy. The escalation of the war was partially based on maintaining global perceptions of U.S. resolve against communism, as well as internal concerns about admitting any weakness in Vietnam policy.