of the Primo de Rivera dictatorship (which banned all anarchist organizations and publications), created a lull in anarchist activity. Many anarchists responded to police violence by becoming themselves. This was a period of mutual violence, in which anarchist groups including assassinated political opponents. Many anarchists were killed by gunmen of the other side. FAI During the Primo de Rivera years, much of the CNT leadership began to espouse a "moderate" revolutionary syndicalism, ostensibly holding an anarchist outlook but holding that the fulfilment of anarchist hopes would not come immediately, and insisting on the need for a more disciplined and organised trade-union movement in order to work towards libertarian communism. The (FAI) was formed in 1927 to combat this tendency. Its organization was based on autonomous affinity groups. The FAI remained a very secretive organization, even after acknowledging its existence two years after its formation. Its surreptitious nature makes it difficult to judge the extent of its membership. Estimates of FAI membership at the time immediately preceding the revolution range from 5,000 to 30,000. Membership dramatically increased during the first few months of the Civil War. The FAI was not ideally libertarian, being dominated by very aggressive militants such as Juan García Oliver and Buenaventura Durruti. However, it was not authoritarian in its actual methods; it allowed freedom of dissent to its members. In fact the overall organization of the FAI was very loose, unlike Bakunin's "Alliance" which was, however, an important precedent in creating an organization for pushing forward anarchist ideology. The FAI was militantly revolutionary, with actions including bank robberies to acquire funds, and the organization of general strikes, but at times became more opportunist. It supported moderate efforts against the Rivera dictatorship, and in 1936, contributed to establishment of the Popular Front. By the time the anarchist organizations began cooperating with the Republican government, the FAI essentially became a de facto political party and the affinity group model was dropped, not uncontroversially. Fall of Rivera and the Second Republic The CNT initially welcomed the Republic as a preferable alternative to dictatorship, while still holding on to the principle that all states are inherently deleterious, if perhaps to varying degrees of severity. This relationship did not last long, though. A strike by telephone workers led to street fighting between CNT and government forces; the army used machine guns against the workers. A similar strike broke out a few weeks