With a ceasefire in the U.S.-Israel-Iran conflict now in force (albeit under stress), it is unclear whether U.S. President Donald Trump intends to continue direct U.S. military involvement in Iran much longer. As such, any significant regime change in Iran through direct military action – which was a key objective for the United States going into this war – seems increasingly out of reach. Nonetheless, fighting between Iran and Kurdish rebel forces has continued despite the ceasefire, and it is expected that Kurdish forces will resume attacks against the Iranian government. This follows reporting suggesting that Kurdish rebel forces had begun launching ground offensives in Iran before the ceasefire, with preparations being made for a large-scale operation to overthrow the regime. Under these circumstances, providing covert and material support to Kurdish insurgency in Iran to effectuate regime change may become an attractive option for the United States to attain its long-term objectives in Iran.
In fact, recent reporting seems to confirm that the United States had already been planning to support a Kurdish invasion of Iran to effectuate regime change, with plans in place for “tens of thousands of armed Kurdish fighters … under ‘massive’ US and Israeli air cover.” Trump also recently confirmed that the United States had “sent [the Kurds] a lot of guns.” Though the current state of the relationship between the U.S. and Kurdish forces is not known, Kurdish fighters continue to seek and expect American support in launching a ground insurgency to topple the Islamic Republic. Therefore, whatever the future of American involvement in Iran may be, Washington’s relationship with Kurdish rebel forces may soon become a central feature of U.S. engagement.
Such a relationship with Kurdish forces would, however, not only potentially further compound the illegality of U.S. actions in Iran, but also be unwise and ineffective, as lessons from history demonstrate. Several leading experts and commentators have already explained the illegality of the joint U.S.-Israeli strikes in and against Iran (see here, here, here and here). The United States has already committed serious breaches of international law governing the conduct of hostilities, including the strike that resulted in the deaths of over a hundred schoolgirls. Providing assistance to the Kurds would introduce a new layer of illegality. Specifically, the United States would find itself in a continuing (and yet another) breach of the rules on non-intervention which would persist even beyond and irrespective of the ceasefire or any potential long-term agreement, and could, depending on the facts, also incur State responsibility for violations committed by Kurdish forces. This would depend a great deal on the specific modes, intensity, and nature of the assistance provided and the relationship established between the United States and Kurdish armed opposition forces. It is thus crucial that these facts and specificities are rigorously and continually investigated by Congress to ensure that it does not inadvertently appropriate additional funds for the war in Iran which may be used in a clandestine and illegal manner as the U.S. has done in the past.
The Principle of Non-Intervention and the Nature and Extent of U.S. Assistance to Kurdish Non-State Armed Groups (NSAGs)
Customary international law prohibits coercive intervention in the internal affairs (or domaine réservé) of another State. Indeed, the principle of non-intervention is recognized as one “of the most fundamental principles and rules of international law” (Armed Activities, Reparations, para. 65). It is equally well recognized that providing material support to NSAGs and armed insurgents is “an established form of prohibited intervention” (Kriener, para. 24). This is codified in Principle (c) of the Friendly Relations Declaration, expressing “[t]he duty not to intervene in matters within the domestic jurisdiction of any State, in accordance with the Charter.” The Declaration further provides that “no State shall organise, assist, foment, finance, incite or tolerate subversive, terrorist or armed activities directed towards the violent overthrow of the regime of another State.”
While the United States has already violated this principle of non-intervention by engaging in the use of force to attempt regime change, providing assistance to NSAGs in Iran would not only be yet another violation, but also one that will likely outlast the United States’ direct military involvement in Iran. Though direct military action contrary to the rules governing the use of force will always constitute a prohibited intervention, it is not a necessary condition for the violation of the non-intervention principle. As such, the United States may be in a continuing breach of the principle of non-intervention if it is providing assistance to Kurdish NSAGs notwithstanding a ceasefire or a military withdrawal from Iran.
The analysis with respect to whether U.S. assistance to armed Kurdish groups amounts to a prohibited intervention turns in part on a key set of facts: the nature and extent of support that the United States provides. In Nicaragua, the International Court of Justice (ICJ) characterized assistance as a prohibited intervention when it involves support “either in the direct form of military action, or the indirect form of support for subversive … armed activities” (para. 205). Though the Court did not define the precise standard for what may constitute indirect support, it found that the United States committed a “clear breach” of the principle of non-intervention by providing financial support, training, supply of weapons, intelligence, and logistical support to the contras in Nicaragua (para. 242).
The extent of support that the United States is either already extending to or planning to extend to Kurdish fighters is unclear. A CNN report suggested on March 4 that the CIA is planning to “arm” and provide “military support” to Kurdish opposition groups. If true, this would clearly be a case of, at the very least, providing a supply of weapons and logistical support that was found to constitute a “clear breach of the principle of non-intervention” in Nicaragua (para. 242). (Following the Court’s judgement in Nicaragua, such support could also constitute a prohibited use of force.)
The day after the report, however, the Trump administration was quick to walk back its position on providing any form of material support to Kurdish groups. In a press conference, Trump stated that though he “[does not] want the Kurds to go into Iran,” he would “be all for it” should they choose to do so. Secretary of Defense Pete Hegseth also remarked that “none of [the United States’] objectives are premised on the support of the arming of any particular force.” This, however, does not necessarily absolve the United States from responsibility for prohibited intervention in the event of a Kurdish insurgency for two reasons.
First, the United States has, in fact, provided a range of support to the Kurds with the aim of fomenting or supporting an insurgency. A Chatham House expert comment noted, for example, that the United States is “aiming to potentially prepare the ground” for a Kurdish offensive by “heavily bombing targets in Kurdish areas in western Iran.” Multiple sources also told CNN that the Trump administration had been in “active discussions with … Kurdish leaders about providing them with military support.” And the three main Kurdish opposition groups formed a coalition to overthrow the Islamic Republic only a week before the Feb. 28 strikes by the United States and Israel. Taken together, these developments suggest that the United States and Kurdish NSAGs have been acting in concert. Though a spokesperson for Iraqi Kurdistan stated that the United States is not arming Kurdish fighters in Iran, this does not entirely rule out some relationship of cooperation and support that would reach the threshold for intervention, given it can be met by supportive acts falling far below the level of providing arms.
Second, and perhaps more importantly, it is likely irrelevant as a matter of law whether or not the United States is providing any material support to the Kurds of the kind that was found to be unlawful in Nicaragua. While such support would be relevant to a use of force analysis, in contrast, the prohibition on intervention includes the “incitement” or “tolerance” of subversive actions by insurgents geared towards achieving regime change. This standard is found squarely within the text of Principle (c) of the Friendly Relations Declaration which is considered to be “declaratory” of customary international law (Armed Activities, Merits, para. 162). For the purposes of a breach of the principle of non-intervention, therefore, it may be enough that the United States merely welcomes or creates conditions conducive to a Kurdish offensive against Iran.
While the precise contours of what it means to “tolerate” – or even “incite” – intervention are not well elaborated, it seems likely that the threshold was already crossed when the United States encouraged the Kurds to overthrow their government. Going further, the United States has already “targeted Iranian military positions along the Iran–Iraq border, degrading command nodes, air defenses, and logistics networks that previously constrained Kurdish insurgent activity,” ostensibly to create “space for Kurdish forces to maneuver” against the Iranian state. Thus, any future Kurdish action would necessarily occur “in an ‘operational environment’ already shaped” by U.S. military action against Iran. In sum, it is highly likely that U.S. support already provided to Kurdish armed groups – material or otherwise – would leave the United States in breach of the principle of non-intervention.
State Responsibility for Internationally Wrongful Acts Committed by Kurdish NSAGs
Given the potential for a Kurdish ground operation in Iran, it is also worth considering whether the Kurdish NSAGs’ conduct during these operations may be attributable to the United States. Under Article 8 of the Articles on State Responsibility (ARSIWA), the conduct of a non-state actor may be attributable to a State if it is “in fact acting on the instructions of, or under the direction or control” of the State in carrying out its conduct. Unlike for non-intervention, the threshold for State responsibility is one of control over conduct and not mere support or assistance.
However, there is some academic debate and uncertainty over the correct standard of control. In Nicaragua, the Court adopted a strict standard of “effective control,” which required that the State “directed or enforced the perpetration of the acts” (para. 115). This is generally understood to set a very high bar for attribution and requires either (1) the issuance of specific directions or instructions to carry out specific operations, or (2) the “enforcement … of each specific operation” (Cassese, p. 653). Consequently, the “effective control” test would essentially require a proxy relationship between the State and the NSAG.
In Tadic, however, the International Criminal Tribunal for the former Yugoslavia (ICTY) propounded a lower standard. In that case, the ICTY had to consider whether the Bosnian War was of an international character to determine liability under Article 2 of the ICTY Statute which applied only to international armed conflicts. Here, the ICTY adopted an “overall control” standard in relation to the attributability of group conduct to a State (para. 131). This is a more flexible standard of control under which there is no requirement for the issuance of specific instructions so long as the State “has a role in organising, coordinating or planning the military actions of the military group” (para. 137). The ICJ, however, pushed back against this standard strongly in Genocide whilst assessing State responsibility for violations of the Genocide Convention during the Bosnian War, and reasserted the stricter effective control test.
A choice between these two tests may not matter if the United States is only providing the Kurds with weapons, equipment, logistical, and financial support – as current reporting suggests. Even training Kurdish forces would not necessarily move the needle. This is because even on the more flexible “overall control” test, it is uncontroversial that such forms of material assistance and operational support are not enough for an NSAG’s subsequent conduct to be attributable to the State (Tadic, para. 137). That is also why the ICJ refused to hold the United States responsible for the conduct of the contras in Nicaragua even though the level of cooperation there was manifestly greater than current ties between the United States and Kurdish opposition forces appear.
Since there must, at the very least, be some State role in organizing, coordinating, or planning military operations, a lot turns on the precise content and nature of the CIA’s reported discussions with the Kurdish forces. Though merely sharing intelligence or acting in concert may not satisfy even the overall control threshold, this changes if the CIA begins providing strategic or tactical assistance or guidance to Kurdish NSAGs.
Of course, such assistance between allies cannot alone imply any degree of “control” (Tadic, para. 130). What is required is that there be an exercise of control “by coordinating or helping in the general planning of its military activities” (Tadic, para. 131). Thus, the relevant question is not just whether there is coordinated planning between the United States and Kurdish NSAGs, but whether the United States is planning and coordinating military operations for the Kurdish NSAGs such that the latter are acting broadly on the directions of the former. The overall control standard may be met only if the United States did or is, in fact, coordinating military activities with Kurdish NSAGs as part of a broader plan which also involves some broad direction of military operations. The United States’ heavy bombardment of certain areas within Iran to clear the way for Kurdish forces may, for example, be indicative of some level of coordinated planning of military operations being undertaken by the United States for Kurdish forces. How much, however, we cannot be certain based on what has been publicly reported to date.
The attribution of the conduct of Kurdish NSAGs to the United States on the basis of an “effective control” test is even more unlikely. In practice, support by States to NSAGs rarely rises to the level of issuing specific instructions to carry out specific operations. Though rare exceptions exist – such as violent uprisings by pro-Russia groups in Donbas in 2014 (Russian effective control was affirmed by the European Court of Human Rights) and the Bay of Pigs invasion in Cuba – by and large, the history of internationalized armed conflicts and U.S. cooperation with NSAGs reveals that State-NSAG relations have hardly ever risen to the level of specificity required by the “effective control” test. This is because, while States may provide a great deal of strategic guidance, goal-setting, and material support to NSAGs, the specific targets, means and methods of warfare are generally left to the NSAG so long as there is alignment over broader strategic goals. In Armed Activities, for example, the ICJ declined to attribute the conduct of the Movement for the Liberation of Congo (an NSAG) to Uganda despite finding a high, albeit non-specific, level of joint planning and coordination (para. 160). Given that Kurdish NSAGs have long existed and carried out operations independently, they are unlikely to form a true “proxy” type of relationship with the United States.
Concluding Thoughts
The United States’ modus operandi of working in tandem with NSAGs to achieve regime change has always created more problems than it has solved. The complex plan to fund the contras to overthrow the Sandinista government in Nicaragua, for instance, not only failed to achieve regime change but also brought a panoply of legal consequences and plunged the United States into the deeply damaging Iran-Contra scandal, which involved the Reagan administration selling arms to former Iranian Supreme Leader Ruhollah Khomeini. Similarly, the al-Qaeda terrorist organization was born out of “a network of Arab and other foreign veterans of the US-backed Afghan insurgency” during the Soviet-Afghan war. CIA assistance, funding, and training to mujahideen forces in Afghanistan through the 1980s, therefore, had the devastating “blowback” of giving birth to one of the most significant global terrorist threats in history.
The American habit of supporting NSAGs to achieve shared strategic objectives while turning a blind eye to ideology and international law has proven to be myopic time and again. This pattern now risks repetition in Iran; though both the United States and Kurdish NSAGs may benefit from seeing the Islamic Republic fall, there seems to be no contemplation of the consequences of a successful Kurdish rebellion for peace, justice, and stability for the Iranian people and in the broader Middle East. In fact, if anything, an effective Kurdish rebellion would be likely to spark a violent civil war – the most devastating costs of which would be borne by the Iranian people. These strategic consequences notwithstanding, of course, providing support to Kurdish forces in Iran would also constitute yet another flagrant violation of international law. The U.S. Congress must learn its lessons from the challenges of uncovering the Iran-Contra affair and take a proactive oversight role in investigating the intelligence community’s activities in Iran, and should not appropriate funds for further violations of international law in Iran.
