International humanitarian law prohibits or restricts the use of conventional weapons in order to moderate the effects of wars on civilian populations.

Customary law gives rise to regulations such as:

• the prohibition of weapons that may have indiscriminate effects
• the prohibition of weapons that cause unnecessary suffering.

The Convention of 1980 and its 5 protocols
The Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons (CCW) of 10 October 1980, widely known as the Inhumane Weapons Convention, is crucially important. In addition to the general framework convention, the three annexed protocols prohibit or restrict the use of certain categories of weapon:

• Protocol I on non-detectable fragments
• Protocol II on mines, booby traps and other devices
• Protocol III on incendiary weapons.

The Convention, which was designed to be flexible, has been amended in the light of the rapid development of weapons technology and methods of warfare since 1980. Its scope has been extended by three further protocols:

• Protocol IV on blinding laser weapons (1995)
• Amended Protocol II on mines, booby traps and other devices (1996)
• Protocol V on the explosive remnants of war (2003).

In addition to the regulations on behaviour in armed conflict, the Convention also provides for measures covering the periods preceding the commencement of hostilities and following their cessation. The scope of the Convention was extended to cover conflicts within state borders in 2001. This expansion to the scope of the Convention takes account of the shift in the nature of contemporary armed conflicts in recent decades.

Switzerland has ratified the framework convention and its five protocols. It is actively involved in the work of government experts on regulations for other types of weapon that the Convention does not yet cover. 

Rules regarded as customary international law
Switzerland also supports efforts beyond the scope of the CCW to restrict or ban weapons that have serious humanitarian consequences. 

As with any use of weapons in an armed conflict, the use of cluster munitions and anti-personnel mines, for example, is restricted by the general rules and principles of international humanitarian law. In particular, the latter stipulates which measures must be taken to minimise the consequences of the conflict on the civilian population and civilian objects. The most important rules of international humanitarian law that apply to the use of weapons are:

• the obligation to distinguish between civilian objects and military objectives,
• the ban on indiscriminate attacks,
• the obligation to respect the principle of proportionality, and
• the obligation to take steps to minimise the consequences of an attack for the civilian population.

These rules are a part of customary international law and therefore apply to any party to a conflict – governments as well as non-government armed groups – regardless, of whether a country is party to the relevant treaty under international law. 

Conventions on Cluster Munitions and Ânti-Personnel mines
Both chambers in Switzerland’s parliament ratified the Convention on Cluster Munitions on 30 May 2008 which follows in spirit the Convention on Anti-Personnel Mines of 18 September 1997, and which Switzerland was one of the first countries to ratify, on 24 March 1998. Owing to the serious humanitarian consequences of these weapons, both Conventions stipulate a comprehensive ban on their use, development, production, purchase, transfer and storage.