A popular uprising will topple the “dictatorship in Israel” unless it yields to the demands of the J14 social protest movement, one of its activists warned on Saturday.Barak Cohen, an attorney identified with the movement, which came to the fore during this past summer’s mass protests, posted a scathing letter addressed to the Knesset on the movement’s website saying Israel was controlled by a dictatorship that is “destined to fall.”RELATED:Harvard profs: Social-protest movement needs clear demands“The form of regime in Israel is not democratic,” he wrote. “The inability of the citizens to fight against laws passed by the Knesset, as though they were sacrosanct, means Israel does not have a democratic regime.”Cohen added: “In a dictatorship when you want to change something you instigate a rebellion, an uprising. We must be living under a dictatorship!” While he did not call for the use of violence, Cohen said legal efforts to return power to the citizens had exhausted themselves.“Give us our rights or the result will be a rebellion,” he wrote. “This is the only way to resolve the rule of force over civilians.”The J14 social movement is a coalition of loosely tied groups and individuals. In recent months, ruptures have appeared among its leaders – such as the falling out between National Student Union leader Itzik Shmuli and prominent activist Daphni Leef. Stav Shafir, one of the leaders of the social protest movement, declined to answer questions regarding Cohen’s letter. Spokesman Alon Lee clarified that the letter was not endorsed by the movement.The movement has struggled in recent months to maintain a public profile. In a tactical shift, activists abandoned mass street protests and began lobbying MKs to advance its agenda.Thus far the government’s public response to the movement has come in the form of the Trajtenberg Committee for Socioeconomic Change.Some of the committee’s recommendations have been adopted by the government, but social protest leaders say the two-year state budget approved a year ago has prevented the allocation of funds to make significant changes.In what appeared to be the catalyst for the letter, Cohen described how Prime Minister Binyamin Netanyahu passed a two-year budget as a temporary change to a Basic Law, the closest thing the country has to a constitution. The move makes challenging and changing the law, and therefore the budget much more difficult.