Can Israel use self-defence to justify its strike on Qatar under the law?

Israel launched a targeted airstrike on the Hamas leadership in Doha, the capital of Qatar, on Tuesday. Six people were reported killed, including the son of a senior Hamas figure.

Global condemnation was swift. The Qatari government called the strike a “clear breach of the rules and principles of international law”, a sentiment echoed by Turkish President Recep Tayyip Erdogan, Malaysian Prime Minister Anwar Ibrahim, and others.

UN Secretary-General António Guterres called the attack “a flagrant violation of sovereignty and the territorial integrity of Qatar”. The prime ministers of both the UK and Australia also said the strike violated the sovereignty of Qatar.

Even US President Donald Trump, Israel’s strongest ally, distanced himself from the attack:

Unilaterally bombing inside Qatar, a Sovereign Nation and close Ally of the United States, that is working very hard and bravely taking risks with us to broker Peace, does not advance Israel or America’s goals.

So, what does the law say about this? Was Israel’s attack against Hamas on the territory of another country lawful?

Israel’s justification

Israeli Prime Minister Benjamin Netanyahu justified the strike by saying it targeted the political leadership of Hamas in retaliation for two attacks: a shooting in Jerusalem that killed six people and an attack on an army camp in Gaza that killed four soldiers. He said:

Hamas proudly took credit for both of these actions. […] These are the same terrorist chiefs who planned, launched and celebrated the horrific massacres of October 7th.

What does international law say?

Article 2(4) of the UN Charter prohibits the use of force against the “territorial integrity or political independence” of another state.

Any use of force requires either the authorisation of the UN Security Council, or a justification that force is being used strictly in self-defence and in accordance with Article 51 of the UN Charter.

So, does this mean Israel could claim self-defence against Hamas’ leadership in Qatar, if the group did indeed direct the two attacks against its citizens in Jerusalem and Gaza?

The answer is complicated.

Self-defence against groups like Hamas

The International Court of Justice (ICJ) has repeatedly stressed the paramount importance of territorial sovereignty in international law.

As such, it has restricted the use of self-defence to armed attacks that can be attributable to a state, not merely to non-state actors operating from a state’s territory.

After the September 11 2001 terror attacks, the United States and other countries claimed they could use force in self-defence against non-state actors (such as terrorist groups) that are sheltering and operating from another state’s territory, even if that state was not directly involved.

In response to these developments, Sir Daniel Bethlehem, an expert in international law and foreign policy advisor to the UK government, proposed several principles aimed at curtailing this justification within the intent of Article 51.

The “Bethlehem principles”, which remain contested, argue that Article 51 can cover actual or imminent attacks by terrorist groups, but only if necessity (the use of force in self-defence is truly a last resort) and proportionality are satisfied.

Moreover, as a rule, force on another state’s soil requires the consent of that state. The only narrow exceptions are when there’s a reasonable, objective belief the host state is colluding with the group or is unable or unwilling to stop it – and no other reasonable option short of force exists.

Israel argues Hamas’ leadership based abroad in countries such as Qatar, Lebanon and Iran remains part of the command structure that orchestrates hostilities against its soldiers in Gaza and citizens in Israel.

That alone, however, is not enough to justify self-defence according to the Bethlehem principles.

By Netanyahu’s own admission, the objective of the Qatar strike was retaliatory, not to prevent an ongoing or imminent attack.

Questions could also be raised about whether proportionality was observed given the diplomatic context of striking a sovereign state and the potential for disproportionate civilian harm in this part of Doha, which houses many diplomatic residences.

Targeting political leaders meeting in a third state — especially one engaged in mediation — also raises questions about whether force was the only means available to address the threat posed by Hamas in this situation.

Moreover, under these principles, Israel would need to demonstrate that Qatar is either colluding with or is unable or unwilling to stop Hamas – and that there was no other effective or reasonable way to respond to the situation.

Qatar has hosted Hamas’ political offices since 2012 and has been one of the group’s main financial backers since it came to power in Gaza.

At the same time, Qatar has played an important mediation role since the October 7 attacks.

This makes it difficult to argue Qatar is unwilling or unable to neutralise Hamas’ operations from its territory. Its mediation would also suggest there is a reasonably effective alternative to force to counter Hamas’ actions.

Final verdict

Without UN Security Council authorisation, Israel’s strikes on Qatar do appear to be a violation of territorial sovereignty and possibly an act of aggression under the UN Charter.

This is further bolstered by the narrow approach the ICJ has taken on self-defence against non-state actors in third-party states, and its stringent requirements of proportionality and necessity – neither of which appear to have been met here.