Saavedra was the first commanding officer of the Regiment of Patricians created after the ill-fated British invasions of the Río de la Plata. The increased militarization of the city and the relaxation of the system of castas allowed him, as other criollo peoples, to become a prominent figure in local politics. His intervention was decisive to thwart the Mutiny of Álzaga and allow viceroy Santiago de Liniers to stay in power. Although he supported the establishment of a government Junta, as others created in Spain during the contemporary Peninsular War, he desired that criollos had an important role in it (the mutiny of Álzaga was promoted by peninsulars). He advised against rushed actions as well, and as his Regiment was crucial in any action against the viceroy, he denied his help until it was a good strategic moment to do so. The opportunity came in May, 1810, and the May Revolution successfully ousted the viceroy.