High treason can be considered as a violent attack against the existence or order of the state or against sovereigns. In some countries, the law distinguishes treason from treason.
In the UK, crimes that constitute high treason include the plot to murder the sovereign; committing adultery with the spouse or eldest unmarried daughter of the sovereign, or with the wife of the heir to the throne; wage war on the sovereign and adhere to the enemies of the sovereign, giving them help or comfort; and attempting to undermine the legitimately established line of succession.
High treason, in the Italian legal system, is a military crime, provided for by art. 77 of the military penal code of peace.
Already in the Risorgimento period the Austrian penal code regulated the crime of high treason, characterized "by the enormous latitude of this interpretation and its applications".
High treason by the President of the Republic
For the Italian legal system, the high treason of the President of the Republic is mentioned in the Constitution, in articles 90, paragraph II (Responsibility for acts committed during the mandate) and 134, paragraph III (Functions of the Constitutional Court). In order to indict the President of the Republic, Parliament meets in joint session and, by voting, decides whether he should be sent to the Constitutional Court for trial.
Until now, the president has never been indicted.
Normally, the Constitutional Court is made up of fifteen members, one third of whom are appointed by the head of state in charge; in order to avoid a conditional and highly unbalanced vote, the fifteen members already in office are supplemented by another sixteen extraordinary members (who must be eligible as senator), drawn by lot from a special list drawn up by Parliament every nine years.