the proportions of the various parliamentary groups." In order to fulfill its function as the ordinary organ through which popular sovereignty is exercised, Parliament can employ the same investigative and coercive instruments as the judiciary in these inquests. Joint sessions The Parliament meets and votes in joint session () for a set of functions explicitly established by the Constitution. Article 55.2 specifies that these functions are entrenched and cannot be altered. Joint sessions take place in the building of the Chamber of Deputies at Palazzo Montecitorio and are presided over by the President of the Chamber of Deputies ex officio. In this way, the drafters of the Constitution intended to establish an equilibrium with the power of the President of the Senate to exercise the functions of the President of the Republic when the latter is indisposed. Joint sessions take place for the following matters explicitly established by the Constitution: to elect the President of the Republic (in this case, 58 regional delegates are added to the assembly). For the first three votes, a two-thirds majority is required to elect the president. If these fail, subsequent votes only require a simple majority. to receive the President of the Republic's oath of office on election. to vote on the impeachment of the President of the Republic (more than an actual impeachment, it is an accusation of "high treason or attack to the Constitution"; this has never happened). This only requires a simple majority. to elect one third of the elected members of the High Council of the Judiciary. For the first two votes, election requires a three-fifths majority of the delegates; subsequent votes require a three-fifths majority of voting members (i.e. excluding abstentions). to elect five of the fifteen judges of the Constitutional Court. The first three votes require a two-thirds majority; subsequent votes require only a three-fifths majority. to vote on the list of 45 citizens from which sixteen lay members of the Constitutional Court are to be drawn in case of impeachment against the President of the Republic. The same voting system is used as for the election of the judges of the Constitutional Court. There is debate among legal scholars about whether the Parliament in joint session can make its own standing orders. Most scholars think it can, by analogy with the regulation of the Senate in article 65, which explicitly foresees such action. Prerogatives The Chambers of