sentences:  Led by Mario Roberto Santucho, they soon established control over a third of the province and organized a base of some 2,500 sympathizers.The Montoneros' leadership was keen to learn from their experience, and sent "observers" to spend a few months with the ERP platoons operating in Tucumán.The military operation to crush the insurgency was authorized by the President of the lower house, Ítalo Argentino Lúder, who was granted executive power during the absence (due to illness) of the President María Estela Martínez de Perón, better known as Isabel Perón, in virtue of the "Ley de Acefalía" (law of succession).