In the morning, before the arrival of the 2nd Army and the GUEs, Médici occupied Resende and used his cadets to establish defensive positions along Via Dutra, towards Barra Mansa, from where he could resist the loyalists.

The defense mounted by Médici is considered important in forcing Âncora to negotiate, but it was part of a larger context of deterioration in the government's position.

In a meeting with his generals around midnight on 31 March, Amaury Kruel sided his 2nd Army with the coup and ordered the invasion of Rio de Janeiro.

[1] At this time, the Tiradentes Detachment, a unit sent on campaign by general Olímpio Mourão Filho, had already crossed the border between Minas Gerais and Rio de Janeiro and come into contact with the loyalist forces sent from Guanabara and Petrópolis to confront it.

[2] Outside the Rio-São Paulo-Minas Gerais axis, São Paulo's western flank was Mato Grosso, whose 9th Military Region (9ª Região Militar; 9ª RM) was subordinate and loyal to the 2nd Army.

[5] Zerbini did not attend the meeting of generals in São Paulo; having arrived in the city from 18:30 to 19:00, he was called by his superior and commander of the 2nd Infantry Division, Aluísio Miranda Mendes, before entering the HQ.

Their operations staff officer, Captain Willy Seixas, and the battery commanders found that it would be impossible to rise up inside the barracks, as they would be surrounded.

Ustra had realized that the objective of the arrangement was for the most politically reliable elements, Cavalero and the sergeants, to take control, and after protests he managed to get the soldiers and corporal to be his own.

A movement over asphalt would wear out the rubber tracks on the tractors that towed the guns, and the battery would be useless in providing anti-aircraft support to a moving column, as its function was to defend sensitive points and it took hours to get into position.

[14] The 1st Light Tank Battalion (BCCL) from Campinas continued to board trains, although, according to Colonel Cid de Camargo Osório, from the General Staff of the 2nd Army, its movement was delayed by the "internal enemy", which managed to cut off electricity supply.

Colonel Benedicto made a phone call to trusted officers there[d] and they kept the two commanders in the artillery barracks, in the center, far from the city, where they did not interfere with the route.

[20] According to then Colonel Antônio Jorge Côrrea, deputy commander of the academy, inaction would have meant watching with "arms crossed, like eunuchs", as the 1st and 2nd Army fought in Resende, threatening life in the Academic City.

[35] Captain Dickens Ferraz, the artillery instructor, stated that together with other officers, he had so much enthusiasm that, if Médici had not made up his mind, they would have crossed the Itatiaia mountain range to join the Minas Gerais rebels.

[41][42] According to Colonel Osório, from the General Staff of the 2nd Army, Kruel's proposed plan was to mount a defense with the 5th and 6th RIs, the 1st BIB and the BCSv, but Médici refused, as he wanted to place the Cadet Corps on the frontline.

[40] Their participation on the frontline may be surprising in two ways: the use of cadets in combat has a bad record in other countries,[45] and the move of the Military School of Realengo to Resende had been done to keep students away from politics, which had led to the spread of tenentism and then communism.

[46] Initially, from 06:00 to 08:30, a vanguard made up of a cavalry squadron and engineers left to take a defensive position on the heights that dominate Ribeirão da Divisa.

It was made up of a reinforced battalion of the Infantry School-Regiment (REsI),[11] with 800 men,[52] a company of tanks and the 2nd Battery of the Artillery School Group (GEsA).

[70] The difficult situation of the artillery is noted in the testimonies of Captain Ferraz and one of his subordinates, Lieutenant José Carlos Lisbôa da Cunha, an assistant on the fire line.

[71][72] Despite recognizing the disproportion, Captain Ferrari opined that the advance of the GUEs would be difficult with the obstacles in the way and the destruction of the bridges would force it to reach the highway from the other side, where the roads were little better than trails, unfeasible for heavy vehicles.

The situation presented by Correio da Manhã was of a large additional number of 1st Army vehicles well before the Barra Mansa region, which the REsI, if it chose to defect, could resist in the mountains.

[14] There was no exchange of fire; at 15:00 a truce was reached, with both sides remaining in position, faced with a new reality: the arrival of General Âncora to negotiate with Kruel at the academy.

For a few tense moments they thought about opening fire, but then they saw soldiers standing next to the vehicles' passenger compartment, waving white shirts.

[81] After Goulart's departure from Rio de Janeiro, Âncora's authority at the head of the 1st Army (and, on an interim basis, the Ministry of War) began to deteriorate.

His decision to defend the Via Dutra with his cadets is considered to be responsible for preventing the loyalist advance, and ultimately, ending Âncora's resistance to the coup.

[97] The steel hub in Volta Redonda, the Companhia Siderúrgica Nacional (CSN), was a military-technocratic project from the Estado Novo era, a pillar of the Brazil's security and development strategy and still strongly associated with the military.

[99] Volta Redonda was of great importance for the Brazil's left, having been visited by Luís Carlos Prestes, Leonel Brizola, Maurício Grabois and Wladimir Pomar.

Faced with imminent disturbances, industrial director Mauro Mariano activated the pre-existing plan, which aimed to keep the plant running and neutralize the strike.

It was then closed by the intervention of the 1st BIB, which parked an armored vehicle in front of the radio station, but returned to air at 09:00 on orders from Lúcio Meira.

Integrated into the pro-government "Legality Chain", it broadcast messages in favor of the president until 16:20, when it began to obey the orders of the Industrial Director.

[100] At the union headquarters, the possibility of dynamiting the Central do Brasil rail lines to prevent the passage of troops was considered, but the unionists chose to wait for events.