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José Sarney assumed the presidency of Brazil due to the unfortunate and untimely death of his running mate, Tancredo Neves. Neves, the elected president, tragically passed away before taking office, leading Sarney, the vice president-elect, to constitutionally succeed him in the role. This somber turn of events resulted in Sarney's rise to the presidency in 1985, making him the first civilian president after a period of military rule in Brazil.