The Gulf of Tonkin Resolution was a congressional measure passed in August 1964 in response to alleged attacks on U.S. naval vessels by North Vietnamese forces in the Gulf of Tonkin. This resolution granted President Lyndon B. Johnson the authority to use military force in Vietnam without a formal declaration of war, significantly escalating U.S. involvement in the Vietnam War. The resolution was based on reports of incidents that were later found to be exaggerated or misrepresented. It allowed for increased military action and led to a significant deployment of U.S. troops in Vietnam, marking a pivotal moment in American foreign policy during the 1960s.