[14] Juan Perón suffered a series of heart attacks on 28 June 1974; Isabel was summoned home from a European trade mission and secretly sworn in as acting president the next day.

A right-wing paramilitary force, between late 1973 and late 1974 the Triple A had already carried out nearly 300 murders, including that of Professor Silvio Frondizi (brother of former President Arturo Frondizi), Congressman Rodolfo Ortega Peña, activist Father Carlos Mugica, Buenos Aires Province Assistant Police Chief Julio Troxler, former Córdoba Vice-Governor Atilio López and former Chilean Army head Carlos Prats.

It murdered, among others, a criminal court judge, Jorge Quiroga; the writer Jordán Bruno Genta; and the publisher of La Plata's centrist El Día, David Kraiselburd.

[citation needed] Following the murder of Buenos Aires Police Chief Alberto Villar (one of López Rega's closest collaborators in the Triple A) and his wife, as well as amid increasing activity by the ERP in the Province of Tucumán, Perón was persuaded to declare a state of siege on 6 November (suspending, among other rights, habeas corpus).

Censorship also increased markedly, culminating in the closure by decree of one of the leading news dailies in Latin America (Crónica) and several other publications, as well as the banning of Argentine television figures such as talk show host Mirtha Legrand and comedian Tato Bores.

The November 1974 election of a left-wing union shop steward at a Villa Constitución steel mill and its disapproval by steelworkers' leader Lorenzo Miguel (a leading figure in the paramount CGT), resulted in a brutal 20 March 1975 police assault on the facility.

[28] Stacking the State Intelligence Secretariat (SIDE) with Fascists loyal to him, Lopez Rega hastened unprecedented intrigue, culminating in the kidnapping of Jorge and Juan Born, prominent local executives who paid US$60 million for their release (a world record at the time).

[29][page needed] Isabel Perón initially maintained the Social Pact inherited from her husband, and succeeded in enhancing it with reforms such as the enactment in December 1974 of payroll taxes to strengthen the Public Retirement System.

These measures doubled rates and fares and ordered a surprise halving of the peso's value, which, by forcing those who could to stampede towards the U.S. dollar, destroyed the fragile financial balance that had been maintained to that point.

[29][page needed] Consumer prices doubled between May and August 1975 alone,[30] and though sharp, mandatory wage hikes had been negotiated between the government, labor and employers, the resulting shock (known as the Rodrigazo) ignited protest across Argentina, including a two-day general strike by the CGT (the first ever against a Peronist administration).

[26] The president's appointment of a pragmatic economist, Peronist wheelhorse Antonio Cafiero and her 13 September announcement of a leave of absence relieved ample sectors of society, from labor unions to business.

Anxious to placate the exasperated public, the military, hard-line labor leaders (particularly the steelworkers' Lorenzo Miguel), and most other Peronists, on 6 October she and Luder signed new measures giving blanket immunity for the Armed Forces that they may (in her words) "annihilate subversive elements throughout the country" – in effect a nationwide extension of the state of siege that had been imposed in Tucumán.

[11] The measure won her just enough support to return from "sick leave" and on 17 October (on Peronists' historically central Loyalty Day), Perón appeared at the balcony of the Casa Rosada, back at her post.

[32] Interior Minister Ángel Robledo's proposal that elections (scheduled for March 1977) should instead be held in November 1976 was approved by the president during this leave, bringing renewed hope that an increasingly rumored coup d'état could yet be averted.

[29][page needed] The mid-year recession had significantly curbed the growth in imports; but because exports continued to fall, the trade deficit reached a record billion dollars in 1975, nearly depleting foreign exchange reserves.

[29][page needed] The government's 1975 budget had been derailed by the crisis and by earlier commitments to cancel its then still-modest foreign debt, something which even so cost Argentina US$2.5 billion that year, alone.

The resulting budget deficits (over US$5 billion, in 1975) and a series of lockouts in the agricultural and commercial sectors began to reassert pressure on prices after November, leading to hoarding and shortages.

[32] A congressional investigation launched in November over the charity fund embezzlement allegations had meanwhile dissipated her remaining support in Congress, prompting the departure of the second-largest party in the FREJULI alliance, the centrist Integration and Development Movement (MID), and dividing the Peronist caucus into "Vericalist" and "Rebel" factions.

Her administration was dealt further political blows from within her own party by a break in December with the Governor of Buenos Aires Victorio Calabró, who declared that "we won't make it [to the next elections]"[34] and with the resignation in January 1976 of Interior Minister Ángel Robledo, her chief legislative and military point man.

[36] Economy Minister Antonio Cafiero, supported by labor, was dismissed in February, and his replacement, Eugenio Mondelli, announced further shock therapy measures similar to the previous year's Rodrigazo – the Mondelazo.

These measures included steep hikes in utility rates and a new devaluation of the already shredded peso, causing prices to more than double over the next three months (inflation reached a new record of over 700% by April) and leading a new wave of strikes and business lockouts.

[29][page needed] The opposition Radical Civic Union (UCR) initiated impeachment proceedings against the President in February with the support of the "Rebel" Peronist faction in Congress.

[25] The head of the CGE, Julio Broner, left Argentina with his family, altogether; CGT Secretary General Casildo Herreras followed suit, announcing from exile that he had "erased" himself.

The leader of the opposition UCR Ricardo Balbín, while making efforts to form a multi-party congressional crisis committee, held a private meeting in February with Army Chief of Staff Videla and told him, "If you're planning to stage a coup, do so as soon as possible – expect no applause from us, but no obstacles either.

[37] Even as the joint chiefs professed loyalty to La Presidente, the Armed Forces High Command had already given final approval to a coup, code-named 'Operation Aries', when the president returned from her leave of absence in October 1975.

It did not fly her to the Quinta de Olivos presidential residence but to an Air Force base in nearby Jorge Newbery International Airport, where she was formally deposed and arrested.

[45] A judge in Mendoza, Argentina in November 2006 demanded testimony from Isabel Perón, along with other Peronist ministers of her government, in a case involving forced disappearances during her presidency; on 12 January 2007, she was arrested by police in Madrid.

She was charged by the Argentine authorities with the disappearance of Héctor Aldo Fagetti Gallego on 25 February 1976, and for crimes related to her issuance of 6 October 1975 decree calling the Armed Forces to "annihilate subversive elements.