Operation Niagara was conducted in response to which significant event?

Operation Niagara was conducted in response to the Siege of Khe Sanh, which took place during the Vietnam War between January and April 1968. This operation was a coordinated air campaign aimed at supporting U.S. Marine forces defending the Khe Sanh Combat Base against a North Vietnamese Army siege. The operation utilized massive aerial bombardment and close air support tactics, highlighting the importance of airpower in conjunction with ground forces during military engagements of that era.

The Siege of Khe Sanh was a pivotal moment in the Vietnam War, emphasizing the intense combat and strategic significance of the location, making Operation Niagara a crucial response to this dire situation. The other events listed—such as the Battle of Dien Bien Phu, the Fall of Saigon, and Vietnam War protests—occurred at different times and under different circumstances, thus are not related to the onset of Operation Niagara.