The Minas Gerais/Rio de Janeiro theater is more exciting and closer to a proper war campaign, all of it happening in a scenic landscape. It had not one but two "battles", the first decided not just by politics but also by conventional military intimidation.

The state was easily defensible, within reach of Rio de Janeiro and Brasília and with fully committed and integrated military and political elites. It was, however, militarily weak. Several ways were thought up to square the circle:

-Through negotiations with Espírito Santo, securing a port to funnel in weapons in wartime

-Expanding, training for war and integrating into the Army the police force to acquire muscle. It doubled in size in the decade and in 64 had 17.880 men. Training collaborated with the Army and focused on defensive warfare in the state's terrain. Weapons were purchased from Czechoslovakia, received from Army stores and mounted in workshops. This was a reversion to what the state gendarmerie always was, a state army; though they no longer fielded aircraft, artillery and the like they still had rifles, machine guns, mortars and a cavalry regiment.
Pictured are police convoys, marked with the state's triangle

-Accelerated training within the Army itself, as Mourão Filho conducted; the regiment within his reach was of servicemen with only a few months of service when the time came, and he made up for it with intense training. Anyone could've noticed he was up to no good, but they just thought he was mad.

-Mourão Filho's original draft for Operation Popeye, using surprise to make up for the lack of muscle. Specifically it envisioned:
-Moving what he had on hand in the city, the 10th Infantry, 2nd Police, 4th Mech Recon and 1st/4th Howitzers and sneakily entering Guanabara by daybreak
-Seizing the first obstacle on the way, the 1st Tank Battalion in Avenida Brasil
-Detach a force to arrest the President in his palace
-Storm the Army HQ
-If the garrison counterattacks, fight to the death