Siles also had to tackle the difficult issue of disarming the worker and miner militia members who had fought in the 1952 Revolution and who had been allowed to keep their weapons. They had served as a useful counterbalance to the possibility of a conservative or military coup against the Revolution, but were by now serving the growing ambitions of the head of the Bolivian Workers' Center (COB) Juan Lechín. Meanwhile, the Falange Socialista Boliviana party schemed to topple the MNR from power, causing a rather disproportionate repressive backlash that diminished MNR's (and Siles') popularity.