As most people knew, Cambodia was declared neutral territory, so there was no reason to suspect that military presence in the area would be a threat. However, North Vietnamese forces were secretly using Cambodia as an area to ship their supplies and cargo through. Considering that Cambodia was neutral, having North Vietnamese forces retreat to that location after fighting wouldn't have been thought of as dangerous nor threatening. United States President Richard Nixon became aware of these supply lines, and on April 30, 1970, President Richard Nixon gave a televised speech declaring that the United States forces would proceed to invade Cambodia. Seeing as most thought this area was still neutral, President Nixon stated that the United States did indeed have motive for invading Cambodia, that being to stop the Northern Vietnamese supply lines that were stationed in Cambodia and to attack and destroy the Viet Cong bases that were interfering with South Vietnam, one of the United States' allies. The invasion of Cambodia did result in many protests across the United States. More than 200 colleges and universities across the nation closed completely; roughly 400 schools were strongly affected by these strikes and protests. A reason that so many American citizens were upset by this was that some Americans still did not understand why we were going into Cambodia nor did many Americans agree with the United States' decision to do so. In President Nixon's televised speech, he stated that the invasion would help South Vietnam, result in the training of South Vietnamese troops, which would then allow the United States troops to withdraw from fighting and therefor leave Vietnam and head home much sooner.