Which act of Congress gave President Johnson the authority to conduct the war in Vietnam as he saw fit?

The act of Congress that granted President Lyndon B. Johnson the authority to conduct the war in Vietnam was the Gulf of Tonkin Resolution. Passed in August 1964, this resolution allowed the President to use military force in Southeast Asia without a formal declaration of war. It was primarily prompted by incidents in the Gulf of Tonkin involving North Vietnamese forces and U.S. naval vessels. The resolution was significant because it provided a broad mandate for Johnson to escalate U.S. involvement in Vietnam, ultimately leading to the deployment of large numbers of American troops and expanded military operations. The Gulf of Tonkin Resolution was later criticized for enabling the escalation of the Vietnam War without sufficient congressional oversight or debate.