On Sunday, Brazilians will choose between a beleaguered left-wing incumbent and a right-wing challenger. Trade, security and democracy are on the table.

© Dado Galdieri for The New York Times

Luiz Inácio Lula da Silva, the leftist incumbent, and Flávio Bolsonaro, the right-wing challenger, face off in a narrow race that could redefine the future of Latin America.

© Adriano Machado/Reuters