The author revises existing historical accounts of a critical period during the Vietnam War when the North Vietnamese urgently needed economic aid from their Communist allies in order to prepare for the ambitious Tet Offensive in January 1968, and to help the DRV economy survive President Lyndon B. Johnson's bombardment of North Vietnam under Operation Rolling Thunder. Using new evidence from the archives in Hanoi, this article shows that China—not the Soviet Union—was the biggest donor of economic aid to the Democratic Republic of Vietnam (DRV, or North Vietnam) in 1967 and 1968. The new evidence suggests that American intelligence estimates of Communist bloc economic aid to the DRV were incorrect. Misled by inaccurate data, U.S. officials failed to understand the remarkable resilience of the DRV economy to survive U.S. bombardment. An accurate understanding of Communist bloc aid arrangements might have strengthened the arguments of those American officials advocating early peace negotiations with the DRV.