North Vietnam supported the Pathet Lao to fight against the Kingdom of Laos between 1958–1959. Control over Laos allowed for the eventual construction of the Ho Chi Minh Trail that would serve as the main supply route (MSR) for enhanced NLF (the National Liberation Front, the Vietcong) and NVA (North Vietnamese Army) activities in the Republic of Vietnam. As such, the support for Pathet Lao to fight against Kingdom of Laos by North Vietnam would prove decisive in the eventual communist victory over South Vietnam in 1975 as the South Vietnamese and American forces could have prevented any NVA and NLF deployment and resupply if these only happened over the 17th Parallel, also known as the Demilitarized Zone (DMZ), a narrow strip of land between North and South Vietnam that was closely guarded by both sides. It also helped the Pathet Lao win the Kingdom of Laos, although the Kingdom of Laos has American support.