 However, American historian Derek Frisby criticized Westmoreland's view, which he said reflected a failure in understanding Giáp's core philosophy of "revolutionary war".According to Frisby, "Giap understood that protracted warfare would cost many lives but that did not always translate into winning or losing the war.In the final analysis, Giap won the war despite losing many battles, and as long as the army survived to fight another day, the idea of Vietnam lived in the hearts of the people who would support it, and that is the essence of 'revolutionary war'."