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1981 coup d'état attempt

An attempted military coup, known as 23-F, occurred on 23 February 1981, when the Cortes were seized by members of the Guardia Civil in the parliamentary chamber. During the coup, the King, wearing his uniform as Captain-General of the Armed Forces, gave a public television broadcast calling for unambiguous support for the legitimate democratic government. The broadcast is believed to have been a major factor in foiling the coup. The coup leaders had promised many of their potential supporters that they were acting in the King's name and with his approval, but were unable to demonstrate either, and the broadcast — coming just after midnight on the night of the coup — definitively showed the King's opposition to the coup makers.

When Juan Carlos became king, Communist leader Santiago Carrillo had nicknamed him Juan Carlos the Brief, predicting that the monarchy would soon be swept away with the other remnants of the Franco era. After the collapse of the attempted coup however, in an emotional statement, Carrillo remarked: "Today, we are all monarchists." Public support for the monarchy among democrats and leftists, which had been limited before 1981, increased significantly following the king's handling of the coup.

However, this event remains controversial and has led to several alternative theories that cast doubt on the sincerity of the King's defense of democracy. The King had close ties with the leader of the rebellion, who had served him as Secretary General of the Royal Household. Above all, Juan Carlos and the main political parties were aware of a plan to put General Alfonso Armada in charge of the government, particularly in order to crack down on the Basque independence organization Euskadi ta Askatasuna (ETA). Although Juan Carlos strongly condemned the coup attempt — more than six hours after the armed guards invaded Congress — it is still difficult to establish whether he acted out of democratic conviction or because the operation was not going as well as expected, with little support. The reasons for the trial of the coup plotters are still classified.