Participating in General Benjamin Menéndez's failed, September 1951 coup attempt against President
Juan Perón, Alsogaray was promoted to the rank of General following Perón's 1955 overthrow. He later served as
Campo de Mayo training base Commandant, and Commander of the 2nd
Cavalry Division. Alsogaray was named Under Secretary of the Army in 1962-63, and in 1964, Chief of
Gendarmerie, in which capacity he captured the members of an incipient
guerrilla group led by journalist Jorge Ricardo Masetti. He was directly involved in the
Laguna del Desierto incident. Appointed Commander of the 1st Army Corps in January 1966, Alsogaray planned a
coup d'état against the democratically elected President
Arturo Illia; Illia was a moderate figure who had incurred opposition from conservative groups by refusing to annul
Peronist victories in the
1965 mid-term elections (their exiled populist leader, Juan Perón, himself welcomed the prospect of a coup, and of a possible political deal). Alsogaray supported the recently removed Chairman of the Joint Chiefs, General
Juan Carlos Onganía, as Illia's successor; the two generals were allies and had been leading members of the moderate ("Blue") faction of the
Argentine military during their dispute with the hard-line ("Red") faction that marred events in 1962 and 1963. Alsogaray managed military contacts with leading civilians amenable to a coup, and enjoyed the support of Onganía's replacement, General
Pascual Pistarini, as well as the friendship of the Chief of Army Intelligence, General Mario Fonseca. Leading discussions on the structure of the future government, he put forth a blueprint prepared by his influential older brother,
Álvaro Alsogaray, supporting the dissolution of democratic institutions, the enhancement of the
judiciary as the guarantor of rights, and a more
free market-oriented economic policy. A key proposal was the creation of the post of
Prime Minister, who would be given wide purview over policy, and to which the Alsogaray brothers intended that Álvaro be appointed by Onganía. Following the coup, Onganía, who had obtained Pistarini's pledge to leave himself and any other active-duty General out of the new government, nixed Álvaro Alsogaray's proposal for creating a (powerful) Prime Minister's post, denying him even the post of
Minister of Economy of Argentina he had twice previously held. He did, however, name Julio Alsogaray, to whose planning he largely owed the coup's success, to succeed Pistarini as Chairman of the Joint Chiefs in December. Differences had developed by May 1968, however, between Alsogaray and the President, who resisted his input, and whose efforts to control the
CGT labor union (by way of fostering a
corporativist model) were anathema to Alsogaray's
neoliberal ideology. Disputes also arose with the
Internal Affairs Minister, Dr. Guillermo Borda (who opposed any return to democratic rule), and with Alsogaray's successor as head of the important Campo de Mayo base, Major General Cándido López (who favored an early call for elections). Fearing a coup, Onganía decided it was best to "refresh" the three forces' leadership every two years, and informed Alsogaray of his retirement on August 20; rather than wait until the scheduled, October 4 transition, he stepped down as Joint Chiefs Commander on August 26. His own son, Juan Carlos, joined the
Montoneros guerrilla organization, and took part in attacks on the Army in the hills of
Tucumán Province as a commander during the mid-1970s. The younger Alsogaray was apprehended in February 1976 by counterinsurgency forces led by the
Operativo Independencia Commander, General
Antonio Domingo Bussi, and was executed. ==Last years==