The Constitution is composed of 139 articles (four of which were later abrogated) and arranged into three main parts: Principi Fondamentali, or Fundamental Principles (articles 1–12); Part I concerning the Diritti e Doveri dei Cittadini, or Rights and Duties of Citizens (articles 13–54); and Part II the Ordinamento della Repubblica, or Organisation of the Republic (articles 55–139); followed by 18 Disposizioni transitorie e finali, or Transitory and Final Provisions. Articles 13–28 are the Italian equivalent of a bill of rights in common law jurisdictions. Power is divided among the executive, the legislative and judicial branches; the Constitution establishes the balancing and interaction of these branches, rather than their rigid separation.
It is important to note that the Constitution primarily contains general principles; it is not possible to apply them directly. As with many written constitutions, only few articles are considered to be self-executing. The majority require enabling legislation, referred to as accomplishment of constitution. This process has taken decades and some contend that, due to various political considerations, it is still not complete. In order to make it virtually impossible to replace with a dictatorial regime, it is difficult to modify the Constitution; to do so (under Article 138) requires two readings in each House of Parliament and, if the second of these are carried with a simple majority (ie. 50%+1) rather than two-thirds, a referendum. Under Article 139, the republican form of government cannot be reviewed. When the Constituent Assembly drafted the Constitution, it made a deliberate choice in attributing to it a supra-legislative force, so that ordinary legislation could not amend or derogate from it. Legislative acts of parliament in conflict with the Constitution are subsequently annulled by the Constitutional Court.
While Article 8 establishes the liberty of all religions before the law, Article 7 recognises the special status given to the Catholic Church by the Lateran Treaty in 1929. That status was modified by a new agreement between church and state in 1984.
The text of the Constitution has been amended 14 times. Amendments have affected articles 48 (postal voting), 51 (women's participation), 56, 57 & 60 (composition and length of term of the Chamber of Deputies and Senate of the Republic); 68 (indemnity and immunity of members of Parliament); 79 (amnesties and pardons); 88 (dissolution of the Houses of Parliament); 96 (impeachment); 114 to 132 (Regions, Provinces and Municipalities in its entirety); 134 & 135 (composition and length of term of the Constitutional Court). In 1967 articles 10 and 26 were integrated by a constitutional provision which established that their last paragraphs (which forbid the extradition of a foreigner for political offences) do not apply in case of crimes of genocide. Four amendments were passed during the thirteenth legislature (1996–2001), these concerned parliamentary representation of Italians living abroad; the devolution of powers to the Regions; the direct election of Regional Presidents; and guarantees of fair trials in courts. A constitutional law and one amendment have been passed in the first part of the fourteenth legislature (2001–2006), the repealing of disposition XIII insofar as it limited the civil rights of the male descendants of the House of Savoy; and a new provision intended to encourage women's participation in politics. Further amendments are being debated, but for the time being 61.32% of those voting in the 25–26 June 2006 referendum rejected a major Reform Bill approved by both Houses on 17 November 2005 and the attempt to revise Part II appears to have been abandoned or at least postponed indefinitely after almost 25 years. However, the constitution was amended making capital punishment illegal "in the cases provided for by military laws in case of war.