Major instruments of European conventional arms control

One of the main features of the first Cold War in Europe was the large numerical advantage the Soviet Union and the Warsaw Pact had over NATO in terms of major conventional weapons, such as tanks or artillery. In the West, this fuelled fears of a surprise large-scale conventional attack aimed at overwhelming NATO’s defences.

As the Cold War was coming to an end, a window of opportunity opened to deal with this challenge by using arms control measures to reduce the stocks of conventional weapons in Europe and to increase the stability of the NATO–Warsaw Pact relationship.

These were the origins of the Treaty on Conventional Armed Forces in Europe, or the CFE Treaty, signed on 19 November 1990. The Treaty entered into force on 9 November 1992, with 30 participating states.

The original aim of the Treaty was to establish a numerical balance in major weapons between NATO and the Warsaw Pact.

The so-called Treaty-Limited Equipment (TLE) included five categories of weapons:

• tanks
• armoured combat vehicles
• heavy artillery
• combat aircraft
• attack helicopters

Initial ceilings for each side (NATO and Warsaw Pact) were: 20,000 tanks; 30,000 armoured combat vehicles; 20,000 heavy artillery pieces; 6,800 combat aircraft; 2,000 attack helicopters.

Equipment exceeding the agreed limits was to be eliminated through destruction or conversion. The CFE included the host nation consent rule: no foreign conventional forces can be stationed on one’s territory without the agreement of the hosting state. The CFE states were obliged to provide information about their military holdings, update them and allow intrusive on-site inspections on their territory to verify this information.

The Treaty covered the territories of the state parties between the Atlantic and the Ural Mountains, and originally also included provisions for different zones: additional restrictions on the numbers of tanks, armoured combat vehicles and heavy artillery were included for specified areas in Northern and Southern Europe (the flanks).

The CFE Treaty was often referred to as the cornerstone of European security. While the security landscape in Europe was changing rapidly with the dissolution of the Soviet Union and the Warsaw Pact, as well as NATO enlargement, the Treaty (with some corrections reflecting, e.g. the emergence of new countries in the post-Soviet space) provided a foundation of military stability for the continent.

Around 52,000 pieces of Treaty-Limited Equipment were eliminated in accordance with the Treaty between 1992 and 1995. If voluntary reductions are also added, more than 69,000 pieces of Treaty-Limited Equipment were eliminated altogether, including more than 26,000 tanks and 2,600 helicopters. Thousands of inspections and verification visits have been conducted.

As with any treaty as complex as the CFE, there were implementation problems from the very beginning with Russia repeatedly exceeding its Treaty limits for some categories of TLE during its military operations in Chechnya. Armenia and Azerbaijan were accused of non-compliance with the Treaty in the context of the Nagorno-Karabakh conflict.

In 1999, the parties to the CFE reached an agreement on a significant update, or adaptation of the Treaty. Instead of the outdated bloc-based approach and flank zones, new national and territorial limits of equipment holdings were agreed. The Treaty was opened for new states to join.

As well as accepting the Adapted CFE at the OSCE Summit in Istanbul, Russia made a number of political commitments, including pledges to withdraw its Treaty-Limited Equipment and troops from Moldova and close its bases in Georgia. NATO states made it clear that they would not ratify the Adapted CFE if these pledges were not met.

Russia argued that the continued application of the original CFE Treaty was detrimental to its security interests and that the connection made by other countries to Istanbul commitments was unfounded. The Adapted Treaty was ratified by Russia, Belarus, Kazakhstan and Ukraine. Russia called on NATO countries to ratify the Adapted CFE as soon as possible. Since this did not happen, in 2007, Russia suspended implementation of the CFE. After emergency talks on the future of the CFE ended in failure, in 2011, NATO countries and some of their partners stopped providing treaty-related information to Russia and declared that they would not accept Russian inspections.

As one of the consequences of the war on Ukraine and its confrontation with NATO, the Russian Duma decided, in May 2023, to withdraw completely from the CFE Treaty, a decision which took effect in November 2023. In response, 22 NATO countries which were parties to the CFE decided to suspend the operation of the CFE Treaty ‘for as long as necessary’. Some of them had also decided at an earlier point to suspend providing information and accepting inspections from Belarus, due to its participation in the Russian aggression against Ukraine.

Without the participation of Russia, and with NATO members and to some extent also Belarus suspending the implementation of their obligations, the CFE’s importance and restraining function in European security has dramatically diminished.

The Vienna Document focuses on Confidence and Security Building Measures, CSBMs, and risk reduction. These measures are aimed at reassuring all sides about the lack of aggressive intentions of other countries, avoiding accidental or inadvertent escalation and promoting cooperation. They also improve military stability by increasing the level of contact and predictability regarding the actions and plans of other countries, and are seen as elements of a gradual process of helping states to overcome their security dilemmas and move towards the development of cooperative security system. Unlike the legal obligations contained in the CFE and Open Skies Treaty, the Vienna Document is politically binding.

The zone of application of the Vienna Document covers the whole of Europe, the adjoining sea and air space, as well as the territory of the Central Asian countries – also members of the OSCE – with the exception of Mongolian territory.

From the relatively basic measures adopted in the 1960s and 1970s, the range and sophistication of the CSBMs increased significantly in the late 1980s and early 1990s. As the Cold War came to an end, CSBMs were seen as instruments to support a new inclusive security system in Europe. In the process, new or expanded measures were gradually added to the existing set of commitments. They were included in the 1986 Stockholm Document and the Vienna Document adopted in 1990 as well as its subsequent updated editions issued in 1992, 1994 and 1999. The latest version of the Vienna Document agreed by all members of the OSCE was issued in 2011.

Some of the most important CSBMs and risk reduction measures in this document include:

• annual exchanges of military information (budget, organisation of armed forces, equipment);
• exchange of information on military planning and doctrines, exchange of calendars for notifiable military activities;
• risk reduction mechanisms for dealing with military incidents and unusual military activities, for example a sudden concentration of large forces at the border;
• prior notification (42 days before their start, or earlier) and invitation of observers to what are known as ‘certain military activities’. To be notifiable, these activities need to exceed specified thresholds, such as minimum number of troops participating or minimum amount of equipment being used. Observers must be invited to the notifiable activities if they equal or exceed separate, higher thresholds;
• voluntary limits on the frequency of massive-scale exercises;
• military-to-military contacts, including visits to military facilities, port calls, demonstrations of new types of major weapons systems;
• inspections (of areas) and evaluation visits (to units);
• encouragement to agree regional or bilateral CBMs above and beyond the Vienna Document requirements.