BRASÍLIA — President Jair Bolsonaro has galvanized gun culture in Brazil.

His trademark campaign sign was a hand folded into the shape of a gun. One of his first moves in office was to ease gun ownership rules. His three oldest sons, politicians themselves, have been fierce proponents of expanding gun ownership through policy proposals and social media posts.

With their actions, Mr. Bolsonaro and his sons have done more than make it easier for Brazilians to legally get a gun. They have fueled a political and cultural debate over guns that was new to Brazil, but that in many ways mirrors the discussion in the United States, where critics say more guns means more deaths and supporters say guns are necessary for self-defense.

“With disarmament laws, who gives up access to firearms, the decent citizen who only wants to protect himself, or the criminal, who by definition doesn’t follow laws?” Mr. Bolsonaro wrote on Twitter. “The right to legitimate self-defense cannot continue to be violated!”