Brazilian President Artur da Costa e Silva issues AI-5 (Institutional Act No. 5), enabling government by decree and suspending habeas corpus.

Artur da Costa e Silva (Portuguese: [aʁˈtuʁ dɐ ˈkɔstɐ i ˈsiwvɐ]; October 3, 1899 – December 17, 1969) was a Brazilian Army Marshal and the second president of the Brazilian military government that came to power after the 1964 coup d'état. He reached the rank of Marshal of the Brazilian Army, and held the post of Minister of War in the military government of President Castelo Branco.

During his term in office Institutional Act 5 was promulgated. This law gave the President powers to dismiss the National Congress, strip politicians of their offices of power, and institutionalize repressive methods of rule against left-wing parties and individuals. Costa e Silva's government started the most oppressive stage of the military regime against opposition, left-wing activists and suspected communists, which would be continued and expanded under his successor Emílio Garrastazu Médici.