Argentine politician, provisional President of the Republic (1962-1963). Born in Buenos Aires, he/she graduated as a lawyer in 1940 at the University of La Plata and entered to the Radical Civic Union (UCR). He/She moved to Viedma, capital of the province of Río Negro, in the South of the country, to practice his profession, and became the leader of the local UCR. In 1954, he/she was the Vice President of the national UCR. The divided radicalism in 1957 between the supporters of Arturo Frondizi, who embodied a position in favor of lifting the proscriptions to peronism, and Balbín, constituting the largest antiperonist option, Guido was oriented towards the intransigent UCR of Frondizi. In the Constitutional Convention of 1957, convened to legalize the decree's repeal of the reforms to the Constitution of 1949, he/she chaired the IRCU block. The following year, in the election certification that proclaimed the Arturo Frondizi as new President of the nation, he/she was elected national Senator for the province of Rio Negro. In November 1958, to resign the Vice President Alejandro Gómez by disagreements with the first magistrate, Guido was appointed provisional President of the Senate, so it became the direct successor of the President in the event of acefalia.
Still it served on such a character when, on March 29, 1962, President Arturo Frondizi was overthrown by a military coup. The military, in order to give an image of continuity of the civilian Government and observance of constitutional forms, was appointed him interim President, keeping the line of succession. As President, Guido tried to handle a political alternative that contemplate the interests of peronism, but three months after the armed forces imposed a completely antiperonist Cabinet designation. He/She was appointed Minister of economy his Government Federico Pinedo, who decreed a large devaluation that favored the interests of the agricultural exporters. On the fifteenth day Pinedo was replaced by the engineer Álvaro Alsogaray, who imposed a stabilization plan that froze salaries, abolished controls and State regulations, and took other steps that undermined local industry, which had grown under the Government of Frondizi.
The Government of the Guido was immersed in existing open hostilities between rival political groups in the armed forces and that lasted for several months. These groups were divided into the so-called "blue" and "red". The 'blue' represented a Constitutionalist, or legalistic position therefore advocated a quick electoral solution, and sought to avoid the wear generated by Government's direct responsibility. The "colorados" were those who exerted the greatest influence on President Guido and more Peronist force sectors. Hatched dispute in September 1962, when both factions pulled its troops out in the powerless eyes of the President. Temporarily triumphed blue, imposed by General Juan Carlos Onganía as Commander in Chief of the army.
Before the next electoral exit, scheduled for 1963, since the Government has advocated the formation of a front that included Peronists, the IRCU, Christian democracy, entrepreneurs, intellectuals, and sectors of the army. This plan was opposed the Navy, led by Admiral Isaac Rojas, Vice President of the Government arising from the coup that overthrew President Perón in 1955. The military conflict became again the street in April 1963, to just three months of elections. Finally, although the Navy was defeated, he/she managed to impose its criteria, by which it reaffirmed the prohibition to peronism, which in reality never had been raised officially.
The negotiations for the formation of the front continued, now without the military, between frondicistas, the Christian Democrats and the Peronists. After intense discussions, the political front managed to realized and its candidate was Vicente Solano Lima, a Conservative leader who had approached the peronism in 1955 and which was immediately vetoed by the Government of the Guido.
Meanwhile, the UCR of the village, which was the greater antiperonist option for the election, chose a formula that did not include their maximum figure, Ricardo Balbín, perhaps to prevent wear. He/She was then formed by Arturo Illia and Carlos H. Perette, as candidates for President and Vice President respectively.
Finally, on July 7, 1963 were held general elections, in which triumphed the UCRP with 21, 15% of the votes, party which then would get the nomination in the electoral college. On October 12, 1963, President Guido handed over power to the winner, the Cordoba Arturo Umberto Illia. He/She then retired to private life.
In the early 1970's, Guido was appointed by the Peronist Government for an important job in a company that was in the process to the development of the South Patagonian, but resigned after a short period.