Planning in Hanoi for a winter-spring offensive during 1968 had begun in early 1967 and continued until early the following year. According to American sources, there has been an extreme reluctance among Vietnamese historians to discuss the decision-making process that led to the "General Offensive General Uprising", even decades after the event. In official Vietnamese literature, the decision to launch the Tet Offensive was usually presented as the result of a perceived U.S. failure to win the war quickly, the failure of the American bombing campaign against North Vietnam, and the anti-war sentiment that pervaded the population of the U.S. The decision to launch the general offensive, however, was much more complicated.