The study indicated that a Shah/General Zahedi political collaboration, supported by local CIA assets and financial backing, represented a strong probability of overthrowing Mossadeq, provided the guarantee of the CIA's physical and financial support, which was self-described by the CIA as "quasi-legal,"[1] with mobs filling the streets and Mossadeq's orders being ignored.[citation needed] Partially due to this report, in addition to the fear of a communist government overthrow and expansionism in the region, the CIA sought to avoid influence of the Communist Tudeh Party.[citation needed] Also, having the Shah's cooperation meant that the legalization of the new and chosen prime minister would occur.[citation needed] However, solidifying the cooperation of the Shah proved arduous for the CIA, so they pressured the Shah to comply with U.S. plans for overthrowing Mossadeq. The goal was to get the Shah to believe it would be easier to go with the plan rather than fighting it.[citation needed] United States Ambassador to Iran Loy W. Henderson reiterated the Shah's reluctance to name Zahedi as succeeding prime minister, suggesting tactical ways to convince the Shah to cooperate. (Dr. Donald Wilber.