The operational plan for the General Offensive and Uprising had its origin as the "COSVN proposal" at Thanh's southern headquarters in April 1967 and had then been relayed to Hanoi the following month. The General was then ordered to the capital to explain his concept in person to the Military Central Commission. At a meeting in July, Thanh briefed the plan to the Politburo. On the evening of 6 July, after receiving permission to begin preparations for the offensive, Thanh attended a party and died of a heart attack after drinking too much. An alternative account is that Thanh died of injuries sustained in a U.S. bombing raid on COSVN after having been evacuated from Cambodia.