International Law Legal Status of Military Forces Abroad
Joop Voetelink
  • LAST MODIFIED: 25 September 2019
  • DOI: 10.1093/obo/9780199796953-0191


Today, states routinely deploy elements of their armed forces on the territory of other states within the framework of international military cooperation or international military operations carried out with the receiving state’s consent (crisis management operations). It is in the interest of the states sending their forces abroad (sending states), as well as the states receiving these foreign forces with their consent (host states), that the legal position of the visiting forces is abundantly clear. Absent a universal convention covering the status of visiting forces, states and international organizations regularly enter into specific agreements and arrangements setting out the rights and obligations of these forces. These international agreements are part of the international law on military operations and are typically referred to as Status of Forces Agreements (SOFAs). Clearly, SOFAs will not be concluded where armed forces have entered another state’s territory without its consent, e.g., in an armed conflict situation. The legal status of the troops operating on hostile territory is then based on international humanitarian law, in particular the law of belligerent occupation. This specific field of law does not apply between allied states fighting a common enemy. Yet, the presence of a vast number of foreign troops has a marked impact on host states. Not surprisingly, the first set of bilateral agreements that today would qualify as SOFAs were concluded in World War I between a number of Allied states. Drawing from long-standing international practice, the agreements all focused on the exercise of criminal jurisdiction over the visiting forces and granted the sending states exclusive jurisdiction over their service members operating on the territory of other Allied states. During and after World War II, SOFAs evolved into more elaborate instruments covering a wider array of topics of interest to the states involved, such as claims and taxes. The core element of all these SOFAs, however, continued to be the exercise of criminal jurisdiction by either the host states or the sending states over service members of the visiting forces and over associated civilians, such as family members and contractors. States and international organizations in charge of crisis management operations regard SOFAs as an essential requirement to temporarily station armed forces abroad. Consequently, failure to come to an adequate agreement with host state authorities may hamper deployment of the troops or lead to termination of an ongoing operation, as happened in Iraq in 2011, when the United States and Iraq could not agree on the terms of a new SOFA for the US troops stationed in Iraq.


Notwithstanding its relevance, status of forces has not attracted widespread academic attention. Indeed, most textbooks on general international law ignore the subject altogether or address it in a cursory way, often in the context of other international law topics. The literature on jurisdiction and immunities sometimes addresses the status of armed forces deployed in the territory of other than their home state in more detail. Fox and Webb 2013 and Roberts 2016, for example, deal with visiting armed forces in the context of international military cooperation and immunities of international organizations, in particular the North Atlantic Treaty Organization (NATO), the United Nations (UN), and the European Union (EU). Sari 2015 treats in detail jurisdiction and immunities with reference to armed forces. In general, however, this level of detail and analysis is found only in the works of academics and practitioners, such as military lawyers, involved in the highly specialized field of military operational law.

  • Fox, Hazel, and Philippa Webb. The Law of State Immunity. 3d ed. Oxford: Oxford University Press, 2013.

    DOI: 10.1093/law/9780199647064.001.0001

    Landmark work on the law of state immunity. The status of armed forces present abroad is addressed in the chapter on international organizations, focusing on the regime as found in UK law and multilateral agreements, such as the NATO SOFA and mission specific agreements concluded by the UN and EU with regard to crisis management operations led by these organizations.

  • Roberts, Ivor, ed. Satow’s Diplomatic Practice. 7th ed. Oxford: Oxford University Press, 2016.

    Classic work on diplomatic law and practice. The status of visiting armed forces is discussed in the context of peacetime military cooperation (NATO SOFA) and crisis management operations (EU and UN agreements).

  • Sari, Aurel. “The Status of Armed Forces in Public International Law.” In Research Handbook on Jurisdiction and Immunities in International Law. Edited by Alexander Orakhelashvili, 319–371. Cheltenham, UK: Edward Elgar, 2015.

    DOI: 10.4337/9781783472185.00016

    The chapter provides an extensive overview of the rules of international law governing the exercise of jurisdiction over visiting armed forces. It emphasizes the particular position of the armed forces as a state organ tasked with the protection of the state. The author concludes there is no self-contained regime covering the status of the military abroad, making the legal framework a multifaceted one, covering customary international law as well as treaty practice.

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