To create a more stable and secure environment and to deepen the political and economic cooperation between the member states, the European Union had been constantly developing its multi-sectoral structure to ultimately form a union that has no analogy across the world.

The primary law of the European Union is made up of various treaties signed by the member states, which lay the foundation for the EU’s policies and establish its institutional structure, legislative procedures and basic powers.

Such treaties include, for example: Treaty of Rome, Single European Act, Maastricht, Amsterdam and Lisbon treaties.

From the Treaty of Rome to the Single European Act

The relations between the six countries forming the European Coal and Steel Community acquired such a stable and progressive character that it was decided to create the European Economic Community in 1957, by the Treaty of Rome.

In 1955, in the Italian city of Messina, the foreign ministers of the six countries (France, Germany, Italy, Belgium, Luxembourg and the Netherlands) agreed to continue the process of integration. A government committee was formed to prepare the groundwork for the Treaty of Rome. In 1957, the Treaty establishing the European Economic Community was signed in Rome. The same day, the European Atomic Energy Community was established by EURATOM Treaty to ensure the development of atomic energy industry, distribution of energy to the member states of the Community and sale of the remaining resources to non-member countries.

One of the main achievements of the Treaty of Rome was agreement reached on the creation of a common market to lead to the formation of a customs union in the future. The common market envisaged the abolition of barriers to movement of goods, services, capital and people between the member states of the European Union. The Treaty of Rome also laid the foundation for the development of a common agricultural and trade policy.

In 1967, the Brussels Treaty (Merger Treaty) (signed in 1965) unified the above-mentioned three organizations: the European Coal and Steel Community, the European Economic Community (hereinafter the European Community) and the executive bodies of EURATOM – the Commission (hereinafter the European Commission) and the Council into one institutional system called the “European Communities”, which was renamed the European Union in 1992, based on the Maastricht Treaty.

The EU Customs Union was established in 1968, by the Treaty of Rome, which means that the member countries do not charge tariffs on goods traded between them, and they set the same tariffs on goods imported from countries outside of the customs union territory. In the 70s, the development of intergovernmental cooperation in the field of foreign policy began. From 1970 on, the ministers of foreign affairs of the member states met once a quarter to discuss foreign policy issues. A permanent political secretariat was created. Later, this cooperation was institutionalized and European political cooperation was established.

In 1974, the principle of regular meetings of the heads of the member states was formalized. From 1969 to 1974 such meetings were held once a year, and since 1974 – at least twice a year.

Schengen Agreement

By signing the Schengen Agreement on 14 June 1985, Belgium, Germany, France, Luxembourg and the Netherlands agreed to gradually remove controls at their internal borders and to introduce freedom of movement for all nationals of the signatory countries, other EU Member States and some non-EU countries.

Today Schengen Agreement applies to 26 countries, including:

• 22 EU member states: Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Slovakia, Slovenia, Spain and Sweden;
• 4 non-EU European countries: Switzerland, Norway, Iceland and Liechtenstein.
• 4 candidates to entering the Schengen area: Bulgaria, Cyprus, Croatia and Romania.

The aforesaid countries form the Schengen Area. Ireland is part of the EU but not of the Schengen Area

The external borders of the Schengen Area are strictly controlled, whereas internal borders can be crossed without any passport checks. The Schengen Agreement abolishes checks at the signatories’ internal borders and reinforces the EU’s external borders.    Countries are responsible for carrying out a common migration policy, which requires the use of common database and police and judicial cooperation.

Single European Act

The Single European Act was signed at  Luxembourg City on 17 February 1986 and at The Hague   on 28 February 1986, and came into effect on 1 July 1987, to bring amendments to the Treaties establishing the European Communities .   The Single European Act became the first comprehensive revision act to institutionalize European political cooperation, namely: the European Council was established as one of the institutions of the European Union; Court of first instance was created; The Parliamentary Assembly was officially renamed the European Parliament; Co-decision procedure, which strengthened the role of the Parliament; The powers of the commission increased; Majority decision-making procedure began to apply to many areas where previously decisions were made only by unanimity.

The completion of the single market was put on the agenda, and reforms necessary for the creation of the internal market began. This meant the creation of an economic space free from existing barriers (quotas, tariffs) and economic obstacles, guaranteeing  the free movement of goods, capital, services, and people, known collectively as the “four freedoms”.  The creation of the internal market was to be completed by 31 December 1992.

Maastricht Treaty

The fall of the Berlin Wall followed by the reunification of Germany, the liberation of Central and Eastern European countries from Soviet control, as well as the dissolution of the Soviet Union in December 1991 and important democratic processes led to a change in the political structure of Europe.

The Treaty on European Union, known as the Maastricht Treaty, was signed in Maastricht, the Netherlands, on 7 February 1992. With the signing of this treaty, the European Communities were transformed into the European Union, and acquired a political aspect along with the economic one. The Maastricht Treaty amended and brought together in a single text all the previously existing treaties: Treaty of Paris (1950), Treaty of Rome (1957) and Single European Act (1986).

According to the Maastricht Treaty, the European Union comprised three pillars: the first pillar: the existing European Communities (the European Community, the European Coal and Steel Community and the European Atomic Energy Community (EURATOM); the second pillar: the Common Foreign and Security Policy (CFSP); the third pillar:  cooperation in the field of justice and home affairs.

First column: comprises issues relating to customs union, common agricultural policy, single market, trade policy. With the Treaty of Amsterdam, later, other issues were included into this column.

Second pillar: regulates such issues as cooperation on common foreign policy, peacekeeping missions, aid to non-member countries, European security, disarmament and defence financing.

Third column: includes cooperation between the police and judicial systems of the member states on civil and criminal matters, police cooperation, the fight against racism, the fight against drug addiction, terrorism, organized crime, trafficking and human rights violations.

According to the Maastricht Treaty, the issues regulated by the first column are discussed at the supranational (i.e. European) level, decisions are made by the majority of votes, and the decisive role is assigned to the European Commission and the European Parliament, together with the Council. Under the other two columns, the leading role is given to the Council – decisions are made at the national level, by the heads of state and ministers of the member states. Here, consent of all countries, not of the majority, is needed to make a decision. The Commission and the Parliament cannot interfere in the issues regulated by the second and third pillars, i.e. common foreign and defense policy, as well as justice and home affairs.

The point is that the states did not want to entrust such strategically important issues as: security, foreign policy, home affairs and justice to the Commission and the Parliament, since the objective of these bodies was to protect the common European interests and not to pursue the policy of any particular country. (a member of the European Commission or the European Parliament, who may be French by nationality, does not have the right to act on behalf of France and support a decision

Under the Maastricht Treaty, the powers of the European Parliament increased. More specifically, with the introduction of the co-decision procedure, the European Parliament can co-legislate on equal footing with the Council in various areas. It became necessary for the European Parliament to approve the composition of the Commission. In addition, the institution of the European Ombudsman was established to check violations of the EU law.

According to the Maastricht Treaty, it was decided to create the European Economic and Monetary Union, through close coordination of economic policy and the introduction of a single currency – the euro. The European Central Bank was set up for this purpose. The Maastricht Treaty introduced the notion of EU citizenship to be enjoyed automatically by every national of a Member State. The Maastricht Treaty also considered the possibility of developing a common social policy, however, this chapter was eventually removed because the member states deemed social policy, as well as foreign and taxation policy, to be internal affairs of the country. The Maastricht Treaty entered into force in 1993.

Treaty of Amsterdam

In 1997, the Treaty of Amsterdam was signed in the capital of the Netherlands, covering the issues that could not be agreed upon in Maastricht. The main goal of the intergovernmental conference was to create such an institutional system that would smoothly ensure the future enlargement of the European Union and the integration of Eastern European countries into the European institutions. However, in the process of adopting the Treaty of Amsterdam, the main theme of the debate concerned the need to increase the “flexibility” of the EU’s governance system and to create an area of “freedom, security and justice”. Increasing flexibility meant tailoring the structures of the EU’s governing bodies to better suit the EU that had expanded to 15 members by the time new members were still to be accepted.

Other important aspects of the Amsterdam Agreement included cooperation in the areas of justice and home affairs, visa regimes, border control, asylum and immigration policies, police and judicial cooperation in civil matters. In general, the protection of human rights and the rights of non-member countries moved to the first pillar of EU competences within the framework of the Treaty establishing the European Communities. Police and judicial cooperation in criminal matters remained in the pillar of cooperation in the field of justice and home affairs. EU competences in the field of social policy and employment were expanded. In order to intensify police cooperation, the EU Agency for Law Enforcement Cooperation  – Europol was created.

The Treaty of Amsterdam introduced an important new position – High Representative for the Common Foreign and Security Policy, whose functions were entrusted to the Secretary General of the Council. The Parliament’s powers increased through extending the co-decision procedure to a significant number of key activity areas. Besides, it became necessary for the Parliament to approve the new Commission President.

The introduction of the euro

On 1 January 1999, Economic and Monetary Union was established, as provided for by the Maastricht Treaty. More specifically, the euro, as Europe’s single currency unit, came into being on 1 January 1999 as a non-cash payment instrument, and from 1 January 2002, the euro was put into circulation in its cash form, gradually replacing the national currencies.

Currently, the euro is the official currency of 19 out of 27 EU member countries, which together constitute the euro area.  The rest of the countries use national currencies. The euro area includes the following countries:

Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Portugal, Slovakia, Slovenia, Spain.

To adopt the euro, other member states of the EU must meet certain criteria.  This, inter alia, requires having been a member of the European Exchange Rate Mechanism for a minimum of two years.

At the same time, Andorra, Monaco, San Marino and the Vatican have formal agreements with the European Union to use the euro as their official currency. Kosovo and Montenegro introduced the euro unilaterally, but are not officially part of the eurozone and do not have representation in the European Central Bank and the Eurogroup, which consists of the finance ministers of the eurozone countries and makes political decisions regarding the eurozone and the euro.

The Treaty of Nice

In December 2000, an intergovernmental conference in the French city of Nice developed an agreement (Treaty of Nice). It was signed in February 2001 and entered into force in February 2003. The main purpose of the treaty was to prepare the institutional basis for a new wave of enlargement. The Treaty of Nice brought amendmends to the composition of EU bodies and established qualified–majority voting in the Council, changed the number of votes allocated to each Member State, allocating the higher number of votes for the most populated Member States (this system was modified by the Treaty of Lisbon). The Treaty of Nice increased the European Parliament’s powers and  extended the scope of codecision. Qualified majority rule began to apply to a number of provisions, which earlier stipulated unanimity.

One of the achievements of the Nice Summit was the unanimous adoption of the Charter of Fundamental Rights, which consisted of 50 articles on human freedom, economic and social rights.

The Treaty establishing a Constitution for Europe 

The Nice Summit decided to convene a conference by 2004 and revise the Treaty on the European Union and the founding treaties of the European Union within its framework. Based on the declaration adopted by the European Council in Laeken  (Belgium), on 15 December 2001, European Convention was created, which consisted of 15 representatives of the Heads of Member States (1 representative from each state), 30 members of national parliaments (2 representatives from each parliament), 16 members of the European Parliament and 2 representatives of the Commission.

The representatives of the countries that were to become members of the European Union in the near future also participated in the consultations. Former French President Valéry Giscard d’Estaing was approved as the chairman of the convention. The European Convent was tasked with developing a document that included recommendations on the distribution of competences between member states and the European Union, determining the legal status of the Charter of Fundamental Rights, determining the status of national parliaments, and simplifying the existing organizational structure and mechanisms.

On 17-18 June, 2004, at the Brussels Summit, after making a number of modifications, an agreement was reached on the final text of the Constitutional Treaty, and on 29 October 2004, it was signed in Rome. The Constitutional Treaty was an international treaty but it was never ratified as the majority of the population voted against it in referendums held in France and the Netherlands. According to experts, they opposed the use of the term “constitution”, since it was associated with the State, and therefore, the entry into force of the Constitutional Treaty somehow amounted to transformation of the European Union into a state entity. The majority of the population of several member states proved not to be ready to accept this.

Treaty of Lisbon

The Treaty of Lisbon (initially known as the Reform Treaty (full name:  Treaty of Lisbon Amending the Treaty on European Union and the Treaty Establishing the European Community) was signed on 13 December 2007, in Lisbon, Portugal, and entered into force on 1 December 2009. The Treaty of Lisbon preserves the text of the Constitutional Treaty but does no include state-like symbols like a constitution, a flag or an anthem. Based on the Treaty of Lisbon, the European Union takes the place of the Community and becomes legal successor. Besides, the Treaty of Lisbon mainly modifies the institutional set-up of the European Union. Its aim was to create a stonger and unified system of governance for the EU and to enable the EU to carry out a more effective foreign policy and establish a more simplified decision-making processes.

New posts of President of the European Council and High Representative of the Union for Foreign Affairs and Security Policy were created under the Treat of Lisbon.

The Treaty of Lisbon was intended to facilitate a decision-making process, which, with the enlargemet of the EU, was becoming increasingly more and more difficult. To this end, the new treaty restricted the right of veto, instead increasing the rights of the European Parliament and national parliaments.

Voting procedures were amended to introduce the use of qualified majority voting instead of unanimity in over 45 fields.   The codecision procedure  involving the joint adoption of legislative acts by the European Parliament and the Council of the European Union  extended to 83 fields of the first pillar and was renamed Ordinary Legislative Procedure.

Besides, the Lisbon Treaty introduced European Citizens’ Initiative, which means that at least one million citizens from at least one quarter of the EU member States (currently at least 7 countries out of 27 EU member states) now have the right to directly invite the European Commission to bring forward their legislative proposals regarding the areas over which the Member States have transferred competence to the European Union.

Article 50 of the Treaty Lisbon provides for a mechanism for the voluntary withdrawal of a member state from the European Union (EU).