Final answer:
President Nixon vetoed the War Powers Act due to his belief in strong executive authority and concerns that it would undermine U.S. commitments abroad. He feared it would signal a reluctance to support anti-Communist forces, impacting global U.S. influence following the Vietnam War.
Step-by-step explanation:
President Richard Nixon vetoed the War Powers Act of 1973 but was overridden by Congress. Nixon's decision to veto was rooted in his belief that the Act would restrict the executive's ability to respond swiftly and effectively in international conflicts.
Various reasons were cited by Nixon for his disapproval. First, Nixon was committed to the notion of executive authority in matters of foreign policy and war. He also believed in the doctrine of the unitary executive, advocating for a strong presidential control over the executive branch and its ability to act decisively on matters of national security.
Secondly, Nixon believed that the legislation would hamper the United States' ability to support anti-Communist forces globally. After the experience in Vietnam, in Nixon's view, the War Powers Act could signal to enemies and allies alike that the U.S. was unwilling to fully back its commitments abroad, possibly leading to negative consequences like the fall of Saigon and the rise of authoritarian regimes in regions like Angola and Cambodia.
The veto, although symbolic and ultimately overridden, was indicative of Nixon's approach to presidential powers, which favored broad authority in executing foreign policy and conducting military operations.