Colombia's Use of Force in Ecuador Against a Terrorist Organization: International Law and the Use of Force Against Non-State Actors

Tatiana Waisberg
August 22, 2008

1. Introduction

On March 1, 2008, Colombia attacked members of the Revolutionary Armed Forces of Colombia (FARC) located within Ecuador, killing the group's second highest-ranking member and 21 other militants.[1] Ecuador accused Colombia of violating international law in launching the attack. Colombia justified its action under the right to use force in self-defense.[2] Colombia's use of force against a non-State actor located within the territory of another sovereign State joins similar actions taken by other States (e.g., Israel, United States, and Turkey) in the global war against terrorism. This Insight examines the Colombia-Ecuador dispute in light of the controversies in international law about the legality of the use of force by States against non-State actors that enjoy safe haven or refuge in the territory of other sovereign States.

2. The Colombia-FARC Conflict and International Law on the Use of Force

Colombia's March 2008 military strike against FARC personnel located in Ecuador represents the latest development in the Colombia-FARC conflict, which is the longest running and most violent conflict in Latin America.[3] The United Nations (UN) Security Council and the Organization of American States (OAS) have determined that FARC violence against Colombia constitutes acts of terrorism that threatens peace and security.[4] Both the Security Council and the OAS have stressed, in connection with FARC attacks in Colombia, the international legal obligation UN and OAS Member States respectively have not to support terrorism and to deny terrorist groups safe haven or refuge within their territories.[5] FARC's use of Ecuadorian territory for safe haven and as a base to launch attacks within Colombia is well known. Ecuador had not acted effectively against FARC forces within its territory, but, until March 2008, Colombia had refrained from using military force against FARC units located in Ecuador.

The Colombian use of force against FARC within Ecuador again raised the question whether States are justified under international law in using force directly against terrorist groups or other non-State actors (e.g., rebel forces) located within the territory of another sovereign State without that State's consent or authorization by the UN Security Council. To be justified under international law, such uses for force must either (1) not violate the prohibition against the use of force against the political independence and territorial integrity of the State in question (UN Charter, Article 2(4)); or (2) fall under the right to use force in self-defense (UN Charter, Article 51).

The main focus in international legal discourse has been on the right to use force in self-defense because State attacks against terrorist groups located in other countries is, without some other legitimate basis, generally considered a violation of Article 2(4) of the UN Charter. For example, the OAS determined that Colombia's attack against FARC in Ecuador violated Ecuador's sovereignty and territorial integrity.[6] The OAS did not expressly address whether Colombia had exercised its right to use force in self-defense, but whether this right applies to actions such as those taken by Colombia is the key international legal question raised by this and similar episodes of States using military force against terrorist groups located within other countries.

3. Use of Force Against Terrorists under the Right of Self-Defense

State practice

As noted above, the United States, Israel, and Turkey have all defended military strikes against terrorist groups located in other sovereign nations as legitimate exercises of the right to use force in self-defense, particularly in circumstances in which those other nations have not taken effective action to prevent terrorist groups from operating within their territories. The United States launched military attacks against suspected terrorists in Sudan (1998) and Afghanistan (2001).[7] Israel has attacked terrorists leaders located in other countries, including most recently Hezbollah leaders and cadres in Lebanon and Syria.[8] In 2008, Turkey launched a major military incursion into Iraq to attack Kurdish militants from the Kurdistan Worker Party (PKK), which Turkey considers a terrorist group.[9] In each of these cases, the State taking military action justified its use of force under the right of self-defense.

In addition, many states, such as those within NATO, the OAS, and the UN Security Council, recognized that the terrorist attacks on September 11, 2001 triggered for the United States the right to use force in self-defense.[10] UN Security Council Resolution 1701 (2006) related to the Israeli-Hezbollah conflict in Lebanon also implicitly recognized Israel's right to respond with military force in defensive operations against attacks launched by Hezbollah against Israel from Lebanese territory.[11]

Other states, such as Arab countries and some developing nations, argue that the right to use force in self-defense only applies in cases of an armed attack by another State, not an armed attack by a non-State actor.[12] Under this view, failure to deny safe haven or to terminate terrorist groups' activities within a State's territory in violation of international law does not constitute a justification for other States to use force under the right of self-defense.

Decisions of the International Court of Justice

The International Court of Justice (ICJ) has not directly ruled in a case involving circumstances such as those in the Colombia-Ecuador dispute. In Nicaragua v. United States (1986), the ICJ ruled that the United States could not rely on the right of self-defense to justify its use of force against Nicaragua.[13] The ICJ held that the level of support Nicaragua provided to irregular forces in El Salvador and Guatemala did not constitute sufficient support to equate the actions of those irregular forces to Nicaragua under international law.[14] Although this case involved irregular military forces, the context of the case was a classic "state v. state" dispute about the legality of the use of force.

The same is true of the ICJ decision in Congo v. Uganda (2005), in which the ICJ rejected Uganda's claim that its use of force against the Democratic Republic of Congo (DRC) was justified under the right of self-defense because the DRC was supporting anti-Uganda rebels.[15] Uganda sought to connect the actions of the anti-Ugandan rebels directly with the DRC,[16] as the United States had sought to connect the actions of irregular forces to the government of Nicaragua. Thus, neither the Nicaragua nor Congo decisions answers the question raised by Colombia's use of force against FARC in Ecuador because no one argued that Ecuador instigated or directly supported FARC's violence against Colombia.

In Advisory Opinion on the Legal Consequences of the Construction of a Wall in the Palestinian Occupied Territories (2003), the ICJ made contradictory statements about the right to use force in self-defense. On the one hand, the ICJ held that Israel could not invoke the right to self-defense in this case because this right only applies "in case of armed attack by one State against another State."[17] On the other hand, the ICJ acknowledged that the UN Security Council had recognized the right of the United States to use force in self-defense after the September 11, 2001 terrorist attacks,[18] attacks not imputable to any State in the manner attempted in the Nicaragua and Congo cases.

Exercising the right of self-defense against non-state actors

Analysis of relevant State practice and ICJ decisions produces uncertainty about whether States have a right to use force in self-defense against terrorist groups or other non-State actors located in the territories of other sovereign States. State practice and the UN Security Council's actions after the September 11 attacks may, however, indicate a trend towards recognizing that a State that suffers large-scale violence perpetrated by non-State actors located in another State has a right to use force in self-defense when (1) that other State proves unwilling or unable to reduce or eliminate the source of the violence, (2) the use of force is proportional to the threat posed by the non-State actor, and (3) the use of force is temporary and does not result in non-consensual occupation or annexation of territory.

4. Resolution of the Colombia-Ecuador Dispute

The manner in which Colombia and Ecuador resolved their dispute merely added to the controversy that permeates this area of international law. As noted above, the OAS considered Colombia's incursion into Ecuador to be a violation of Ecuador's sovereignty, territorial integrity, and principles of international law.[19] Colombia issued an apology to Ecuador for the incursion, and the two countries resumed diplomatic relations.

More broadly, the OAS resolved that "the principle that the territory of a state is inviolable and may not be the object, even temporarily, of military occupation or of other measures of force taken by another State, directly or indirectly, on any grounds whatsoever."[20] This statement rejects any right of a State to use force in self-defense against terrorist groups located in another State without that State's consent, and the OAS resolution never mentions the right of self-defense. Thus, the statement is in tension with the declared policy and practice on this issue of the United States, an OAS Member State, and with the UN Security Council's post-September 11th willingness to consider that terrorist violence can trigger the right to use force in self-defense.

About the Author

Tatiana Waisberg, an ASIL member, is a student at the LLM research program of the Center for Advanced Legal Studies, Buchman Faculty of Law, Tel Aviv University, Israel. Her current thesis discusses 'the argument of self-defense against States that harbor international terrorist organizations as a challenge to Westphalian sovereignty'. She holds a LLM degree in international law from the Catholic University of Minas Gerais, Brazil. She is a Lawyer and member of the Brazilian Bar Association. She was an associate Professor of international law at the Catholic University of Minas Gerais.


[1] The Economist. Colombia and its neighbours: on the warpath. The Economist. Print edition. Mar. 8, 2008, at 53

[2] Declaration of the Ministry of Foreign Relations of Colombia from March, 2nd, 2008. Comunicado del Ministerio de Relaciones Exteriores de Colombia No. 081 'Por lo pronto, anticipamos que Colombia no violo soberania sino que actuo de acuerdo con el principio de legitima defensa.' (From now, we anticipate that Colombia did not violate the [Ecuador's] sovereignty but has acted according to the principle of self-defense). Available at

[3] For an in-depth assessment of Colombia root's causes of armed struggle see 'Marco Palacios. Between Legitimacy and Violence: A History of Colombia, 1875-2002. Translated by Richard Stoller. Duke University Press (2006) See also Rafael Pardo. Colombia's Two-Front War. Foreign Affairs, July/August (2000).

[4] UN/S/RES/1465 (2003) characterizes the February 7th, 2003 bomb attack in Bogotá as an act of terrorism that threatened peace and security, and urges all States, in accordance with their obligations under resolution 1373 (2001), to work together urgently and to cooperate with and provide support and assistance, as appropriate, to the Colombian authorities in their efforts to find and bring to justice the perpetrators, organizers and sponsors of this terrorist attack. OAS/CP/RES. 837 (1354/03) condemned the February 7th, 2003, terrorist attack, and decided to ratify the commitment of the member states to step up actions for the strict observance of the provisions of United Nations Security Council resolution 1373 and the Inter-American Convention Against Terrorism concerning the obligation to refrain from providing any form of support to entities or persons involved in terrorist acts, while also reaffirming the unwavering commitment of the member states to deny refuge and/or safe haven to those who finance, plan, or commit acts of terrorism in Colombia or who lend support to such persons, noting that those responsible for aiding, supporting, or harboring the perpetrators, organizers, and sponsors of these acts are equally complicit.

[5] UN/A/RES/60/288 (2006), known as the UN global counter-terrorism strategy, member States adopt a plan of action, including a number of measures to prevent and combat terrorism, in particular by denying terrorists access to the means to carry out their attacks, to their targets and to the desired impact of their attacks. OAS/AG/RES. 2146 (XXXV-O/05) exhort member states to adopt as applicable, in conformity with Articles 12 and 13 of the Inter-American Convention against Terrorism, appropriate measures in accordance with the pertinent provisions of domestic and international law to ensure that neither refugee status nor asylum is granted to persons in respect of whom there are reasonable grounds for considering that they have committed an offense established in the international instruments listed in Article 2 of the aforementioned Convention.

[6] OAS/CP/RES/ 930 (1632/08) considered that on the morning of Saturday, March 1, 2008, military forces and police personnel of Colombia entered the territory of Ecuador, in the province of Sucumbíos, without the express consent of the government of Ecuador to carry out an operation against members of an irregular group of the Revolutionary Armed Forces of Colombia who were clandestinely encamped on the Ecuadorian side of the border; and That that act constitutes a violation of the sovereignty and territorial integrity of Ecuador and of principles of international law.

[7] As a response to the 1998 terrorist bombings on the U.S. embassies in Kenya and Tanzania, the United States attacked Sudan and Afghanistan with the intent to exterminate Osama Bin Laden, the supreme leader of Al Qaeda. See Thomas M. Franck. Recourse to Force: State Action Against Threats and Armed Attacks. Cambridge University Press. (2002), p. 94-96. On October 7, 2001, the United States-lead coalition initiated a large-scale armed incursion into Afghanistan territory in response to September 11th terrorist attacks. Operation Enduring Freedom, as it was denominated, had at least three major goals: capture Osama Bin Laden, eradicate Al Qaeda terrorist safe havens and promote regime change in Afghanistan. The United States claimed self-defense against Sudan in 1998 in response to the terrorist attacks against its embassies in Kenya and Tanzania on August, 7th, 1998. UN/S/RES/1189 (1998) condemned the terrorist attack, while UN/S/RES 1267 (1999) established the Al-Qaeda and Taliban Sanctions Committee, which charged the Taliban with serious violations of international law by sheltering, training of and planning of Al Qaeda terrorist attacks resulting from its continuing use of Afghan territory. These resolutions worked as a legal basis for invading Afghanistan in 2001, in response to the September 11th attacks, along with UN/S/RES/1368 and UN/S/RES/1373 (2001) which recognized the United States inherent right of self-defense according to article 51 of the UN Charter.

[8] Israel has also engaged in the practice of target killings against Hizbollah, Hamas, PLO and Black September alleged terrorists. Amos Guiora. Targeted Killings as Active Self-defense. Case W. Res. J. Int'l L. 36 (2004). On February 1992, Israel killed Sheikh Abas Musawi, head of Hezbollah, in a targeted strike against his convoy in South Lebanon. Again, on February 2008, Israel was accused to have been behind the targeted killing of another Hezbollah leader, Imad Mugniyah, the second in command of the organization, in the heart of Damascus, Syria.

[9] On February 2008, Turkey launched a major military incursion into Iraq against the PKK, killing at least 150 PKK fighters. The main goal of Turkey's armed intervention into northern Iraq military operation was to destroy PKK bases. The Economist. The Kurds: Turkey invades northern Iraq. The Economist. Print Edition. March 1, 2008, at. 42. Turkey's main argument was that 'Iraq has not been able to exercise its authority over the northern part of its country since 1991, for reasons well known, Turkey cannot ask the Government of Iraq to fulfill its obligations, under international law, to prevent the use of its territory for the staging of terrorist acts against Turkey. Under these circumstances, Turkey denies violations of Iraqi sovereignty with the argument that Turkey resorted to legitimate measures to protect its own security in the face of Iraq's inability 'to exercise authority over the Northern part of its country' to prevent 'the use of its territory for the staging of terrorist acts against Turkey'. See UN Doc S/1995/605 (1995) available at

[10] On September, 12th the NATO Council agreed that if it is determined that this attack was directed from abroad against the United States, it shall be regarded as an action covered by Article 5 of the Washington Treaty, which states that an armed attack against one or more of the Allies in Europe or North America shall be considered an attack against them all. See NATO Press Release (2001) 124 available at OAS/RC.23/RES.1/01 adopted on September 21, 2001 recognized the inherent right of individual and collective self-defense in accordance with the Charters of the Organization of American States and the United Nations; UN/S/RES/1368 and UN/S/1373 (2001) recognized the United States right of self-defense according to the UN Charter.

[11] UN/S/RES/1701 (2006) calls for a 'full cessation of hostilities based upon, in particular, the immediate cessation by Hezbollah of all attacks and the immediate cessation by Israel of all offensive military operations'; implying that defensive operations would be admitted. (emphasis added)

[12] The doctrine debate reveals some sources of disagreement between states regarding the scope of the right of self-defense as to respond to non-state actors terrorist acts that reach the threshold of an 'armed attack', according to article 51 of the UN Charter. A restrictive interpretation considers that only armed attacks carried out by States, or on its behalf, may give rise to the right of self-defense.

[13] The ICJ rejected the United States argument of collective self-defense in connection with the military and paramilitary activities in and against Nicaragua, and found that the United States, by training, arming, equipping, financing and supplying the contra forces or otherwise encouraging, supporting and aiding military and paramilitary activities in and against Nicaragua, has acted, against the Republic of Nicaragua, in breach of its obligation under customary international law not to intervene in the affairs of another State. ICJ Reports, 1986, para. 250-253.

[14] Id., para. 195, 230, 247.

[15] The Court found that the conditions for the Uganda exercise of self-defense were not established since the alleged 'armed attacks' were carried out by an anti-Uganda insurgency, the ADF, and 'there is no satisfactory proof of the involvement in these attacks, direct of indirect, of the Government of the DRC. The attacks did not emanate from armed bands or irregulars sent by the DRC or on behalf of the DRC... even if this series of deplorable attacks could be regarded as cumulative in character, they still remained non-attributable to the DRC.' ICJ Reports, 2005, para. 146.

[16] Id., para. 301. Uganda alleged Congolese responsibility for tolerating the rebel movements. Although, this argument was entirely rejected by the Court in respect to the question of self-defense, it referred to the question of 'toleration' in connection with Congolese Government responsibility by saying that "During the period under consideration both anti-Ugandan and anti-Zairean rebel groups operated in this area [DRC territory]. Neither Zaire nor Uganda were in position to put an end to their activities. However ... the Court cannot conclude that the absence of action by Zaire's Government against rebel groups in the border area is tantamount to 'tolerating' or 'acquiescing' in their activities."

[17] ICJ Advisory Opinion (2003), para. 139.

[18] Id. The ICJ stated that notwithstanding Article 51 recognition of the inherent right of self-defense in the case of an armed attack by one State against another State, Israel cannot invoke resolution 1368 (2001) and 1373 (2001) in support of its claim to be exercising a right of self-defense. The ICJ might be implicit admitting the existence of the right of self-defense as a lawful use of force against international terrorist acts.

[19] OAS/CP/RES/ 930 (1632/08).

[20] Id. The principle of non-intervention and the right to territorial integrity are recognized by the Charter of the OAS. According to Article 21, "The territory of a State is inviolable; it may not be the object, even temporarily, of military occupation or of other measures of force taken by another State, directly or indirectly, on any grounds whatever. No territorial acquisitions or special advantages obtained either by force or by other means of coercion shall be recognized."