The party played an important role both directly and indirectly during the pivotal era of Iranian history that began with the 1951 nationalization of the British Anglo Iranian Oil Company (AIOC), and ending with the 1953 overthrow of Mohammad Mosaddeq by a CIA-led coup. The party's policy "fluctuated," first attacking Mosaddeq as `an agent of American imperialism,` then giving him some support during and after the July 1952 uprising. On 15 August a coup attempt against Mosaddeq was thwarted thanks in part to information uncovered by the Tudeh TPMO military network, but two days later party militants inadvertently helped destabilized the government by staging demonstrations to pressure Mosaddeq to declare Iran a democratic republic. As this would have overturned Iran's constitutional monarchy, Mosaddeq reacted by calling out troops to suppress the demonstrators. The party then demobilized late the next day making it unavailable to fight the coup the day after. By 1957 the TPMO was crushed and thousands of party members had been arrested.