Islamic Republic of Iran's attack on the United States' Al Udeid base in Qatar on June 23, 2025, is a significant event in regional security and international law, the analysis of which requires the simultaneous examination of the principles of self-defence and the rights of third States. Al Udeid base, the largest US military base in West Asia, plays a strategic role in regional operations, and the deployment of US forces on Qatar's territory, although based on bilateral agreements, exposes the host country to security risks. Iran has justified its attack as a response to US attacks on its nuclear program and, invoking self-defence, has deemed its action legitimate. Legal analysis shows that while the attack against the US is justifiable within the framework of self-defence, the entry into Qatar's airspace constitutes a prima facie violation of the sovereignty of a third State, from Qatar's perspective.

Within the framework of the rules of neutrality, Qatar, as the host country of the base, is obliged to maintain its neutrality and prevent discrimination between the parties to the conflict. However, the actual situation of Al Udeid base has created a form of practical discrimination in favour of the US and has affected Qatar's framework of traditional neutrality. According to Article 3 of the Hague Convention V, the establishment of communication facilities on the territory of a neutral State is prohibited, and pursuant to paragraph b of the same article, even the use of communication installations established before the war for military purposes is also prohibited. Considering the conditions of Al Udeid base in Qatar, the role of this base in US attacks on Iran can be considered consistent with Article 3 of the Hague Convention V, particularly its paragraph b. According to the judgment of the International Court of Justice in the Corfu Channel case, States have an obligation not to knowingly allow their territory to be used for acts contrary to the rights of other States. Respecting the rights of third States, like Iran, is essential to prevent a violation of neutrality, and bilateral contracts cannot provide a legal justification for violating those rights.

From the perspective of self-defence, Iran's attack on Al Udeid base was primarily carried out in response to the US aggression against Iran's nuclear facilities. In light of Article 2 of the Definition of Aggression resolution, considering the overall "circumstances" and the "gravity" of Iran's actions, this attack cannot be considered an act of aggression against Qatar as a third State. Although the entry into Qatari airspace is a prima facie international violation, this action was not directly carried out with the aim of weakening Qatar's sovereignty, and Iran has officially declared that the target was the United States.

According to Article 2 of the Definition of Aggression resolution, the use of armed force constitutes prima facie evidence of aggression, meaning that the contrary can be proven with stronger reasons. These stronger reasons include the overall circumstances, one important aspect of which is the issue of "gravity". The Security Council's determination in this regard must be "in conformity with the Charter", not an arbitrary determination. The Security Council does not create rules but makes case-specific decisions which, according to Article 25 of the Charter, are binding on States. These decisions, pursuant to paragraph 2 of Article 24 of the Charter, must be within the framework of the principles and purposes of the United Nations. Moreover, regarding the function of the Security Council, Article 24 clearly uses the word "duty", indicating that the Security Council has "responsibility and duty" rather than freedom and discretion. In fact, the actions of the Security Council merely represent the performance of objective and "pre-existing" obligations, meaning that whether the Security Council is successful in performing its duties in practice or not, the "rights" and "obligations" remain in force. The existence of a right or obligation in principle is not contingent upon the determination of the Security Council. In this context, it must be said that determining whether a behaviour constitutes aggression or not has an objective and real criterion, which the Security Council merely identifies. This determination, at least in theory, can also be made by doctrine.

Regarding the overall circumstances of Iran's attacks on Al Udeid base, it is completely clear and obvious that if the US aggression against Iran had not occurred, Iran would never have attacked Al Udeid base in Qatar. Iran was subjected to aggression by two States within twelve days, two States with which it does not share a border, and it is natural that the lack of a shared border limits the options available to Iran for self-defence. Also, the fact that Iran has not committed aggression against any States for many years is an overall circumstance that must be taken into account. In addition, Iran's apology to Qatar and the statements of Iranian officials that Iran's action is not considered an action against Qatar are also significant in this regard. On the other hand, the United States has repeatedly threatened Iran and has numerous military bases around Iran's territory. This is while Iran lacks such facilities around US soil.

The Definition of Aggression resolution in Article 2 uses the word "gravity". This word means both severity and seriousness. Severity can be considered the material element of the behaviour and seriousness its mental element. In other words, severity can include the scale of destruction and damages inflicted, and seriousness can refer to the intent and purpose of the attacking State. From this perspective, the severity of Iran's attacks caused damage to the American base, and certainly the scene of Iran's missiles entering caused fear and concern among the people of Qatar, without considerable damage being inflicted on any person or object outside the US military base. Regarding seriousness, it can be analysed that Iran's intent and purpose was to confront the United States, not to attack against Qatar. Therefore, considering the severity and seriousness, the legal characterization of Iran's attack on Al Udeid base cannot be the same regarding Qatar and the US. In summary, in light of Article 2 of the Definition of Aggression resolution, it must be concluded that the overall circumstances and the gravity of Iran's attacks are such that they cannot be considered aggression against Qatar.

In conclusion, Iran's attack on Al Udeid base, from the perspective of international law, possesses a dual nature: with regard to the United States, it is considered an action within the framework of the right to self-defence; but with respect to Qatar, it is a prima facie violation of airspace sovereignty and an international violation that cannot be considered armed aggression. In a word, Iran's action is a legitimate use of force against the United States, but it is not a use of force against Qatar. Iran's action is a countermeasure against Qatar, but it is not a countermeasure against the United States. Because countermeasures do not include the use of force, the logical connection between the two preceding statements is quite evident. In reality, Iran's action in violating Qatari airspace is an action that under normal circumstances is not permitted, but was carried out in response to the violation of neutrality by that State.