In late January, the United States shot down a 200-foot balloon that had hovered for days over U.S. territory. The “spy balloon” incident heightened tensions between Washington and Beijing, prompting U.S. Sec. of State Antony Blinken to criticize China’s actions as “a clear violation of our sovereignty, a clear violation of international law, and clearly unacceptable.” A White House press statement similarly claimed the spy balloon violated U.S. sovereignty and international law.
There is considerable debate about whether the spy balloon (and the U.S. shootdown of it) violated international law. But the incident also raises deeper questions about the legality and morality of espionage more broadly – questions policymakers must address as States rely on more subtle and pervasive forms of spying through artificial intelligence, mass surveillance, and cyber operations.
International law treats spying that occurs during wartime and peacetime differently. The rules on wartime spying focus on whether the information gathering is carried out through false pretenses. In peacetime, the analysis centers on whether the methods of spying violate a State’s sovereignty.
Espionage During an International Armed Conflict
Under customary international law and international humanitarian law (IHL) (codified in Additional Protocol (I) to the Geneva Conventions, Art. 46) espionage that occurs during an international armed conflict is carefully defined, though the precise methods of information gathering are not identified or prohibited. As the International Committee of the Red Cross notes, “espionage” is the “gathering or attempting to gather information in territory controlled by an adverse party through an act undertaken on false pretenses or deliberately in a clandestine manner.”
During an armed conflict, an individual who engages in espionage is considered a spy and loses her right to prisoner of war status, including the protections around accommodation and access to food, clothing, hygiene and medical care. By contrast, members of the armed forces who wear their own uniforms (as opposed to those who wear civilian attire or the uniform of the adversary) may gather information in the territory of the adverse party without losing prisoner of war status. Similarly, a spy who rejoins her armed forces but who is then captured must be treated as a prisoner of war and incurs no responsibility for previous acts of espionage. If captured, a spy may not face summary execution and is guaranteed the right to a fair trial.
Espionage During Peacetime
Outside of IHL, many international lawyers take the view that there is no general prohibition against espionage. In the Lotus case, for example, the International Court of Justice observed that international law leaves States “a wide measure of discretion which is only limited in certain cases by prohibitive rules” and that in the absence of those rules “every State remains free to adopt the principles which it regards as best and most suitable.” As Ashley Deeks observes:
Several government officials and scholars believe that the Lotus approach provides the best way to think about spying in international law. For them, the idea is simply that nothing in international law forbids states from spying on each other; states therefore may spy on each other – and each other’s nationals – without restriction.
Other scholars disagree, and argue that international law contains an affirmative “right to spy,” (see, for example, this article by Asaf Lubin and his Just Security podcast episode). Many in this camp take the view that spying is necessary for self-defense because States need to gather military and diplomatic intelligence, implying that a rule prohibiting spying would restrict the right to self-defense.
Still other lawyers take a middle approach and argue that some methods of espionage may be illegal because they inherently violate a State’s sovereignty.
The Sovereignty Test
The view that the principle of sovereignty limits espionage begins with international law’s prohibition on States from violating the territorial sovereignty of other States. Sovereignty extends also to territorial seas, via the U.N. Convention on the Law of the Sea (UNCLOS), and to national airspace, via the Convention on International Civil Aviation (Chicago Convention, for a deeper discussion of whether the spy balloon is an “aircraft” under the Chicago Convention see this article by Batuhan Betin). Recently, the non-binding Tallinn Manual 2.0 has tried to define sovereignty as encompassing cyber infrastructure, though disagreements persist as to whether physical damage, or another standard, should determine if a cyber attack infringes upon State sovereignty.
In treaty law, the Vienna Convention on Diplomatic Relations (VCDR) and the Vienna Convention on Consular Relations (VCCR) effectively prohibit receiving States from conducting espionage against the diplomatic and consular missions of sending States. First, diplomatic and consular premises (the buildings or parts of buildings and ancillary land used for the purposes of the diplomatic mission) are inviolable and can only be entered with the consent of the head of mission, except in special circumstances such as natural disasters. Second, diplomatic and consular archives and documents (broadly defined by VCCR Art. 1(1)(k) as “all the papers, documents correspondence, books, films, tapes and registers of the consular post, together with the ciphers and codes, the card-indexes and any article of furniture intended for their protection or safekeeping”) are similarly inviolable. And finally, “official correspondence” belonging to diplomatic and consular missions is inviolable, a provision intended to guarantee secrecy between diplomatic and consular missions and their sending State.
While spying that violates the sovereignty of another State may violate international law, other forms of espionage are officially condoned. For example, international law permits the taking of satellite imagery of another State, based partly on the principle that the “use” of outer space is the “province of mankind.”
Although international law allows for at least some forms of spying in diplomatic relations, individual States often create stricter domestic legislation to protect their national interests. For example, many countries punish corporate espionage such as the stealing of trade secrets or information gathering through cyber hacking.
U.S. federal law criminalizes leaks of classified government information in the Espionage Act, and authorizes the government to collect surveillance information against foreign State adversaries and their agents (see this Just Security series on the Foreign Intelligence Surveillance Act). For instance, Yanjun Xu, a Chinese intelligence officer was given a 20-year sentence for economic espionage and theft of U.S. trade secrets and a National Security Agency employee was indicted for attempting to transmit classified information to a foreign government.
Regardless of whether spying is legal, separate questions arise as to whether it is morally justified and strategically wise. In the case of the spy balloon, U.S. officials repeatedly referred to China’s actions as both illegal and “unacceptable,” alluding to deeper concerns with espionage itself.
While spying is often viewed as an inherently immoral, if commonplace, practice, different normative frameworks may be invoked. According to the “dirty-hands” approach, spying is a necessary evil – government agents must engage in deceit, bribery, and other morally dubious acts to protect national security. Contractarian approaches to espionage, by contrast, suggest that governments have tactically consented to engage in espionage because it is a mutually beneficial practice that allows states to protect their citizens from harm. On this view, spies follow an unwritten moral code – similar to a code of conduct for soldiers – where certain immoral acts, such as lying, become morally acceptable in the context of espionage.
More commonly, the ethics of espionage can be analyzed through the lens of just war theory. The jus ad bellum and jus in bello principles that apply to the use of force may also apply to espionage. An act of spying, for example, may be morally justified if it is conducted at the behest of a legitimate authority, in pursuit of a just cause, and according to the principles of necessity, discrimination, and proportionality.
But just war theory has limited utility for the majority of espionage cases, including the spy balloon incident. The United States and China, for example, are not at war – at least not in the traditional sense of the term – and it is unclear whether and how just war theory should be applied outside of conflict. (Indeed, there are sound reasons to avoid applying just war theory here, as the moral standards governing conduct in war are typically thought to be more permissive than those governing times of peace.)
A better way to conceive of the ethics of espionage is to adopt a rights-based approach, along the lines that Cécile Fabre has proposed. Fabre argues that states have a moral permission, and at times even a duty, to spy based on the imperative of protecting individual rights. This permission is subject to certain conditions: the act of espionage must be necessary to protect against the violation of fundamental rights, and there must be indications from publicly available sources that such violations are imminent. Intelligence operations are morally justified only insofar as they thwart anticipated rights violations and, even then, spies must not cause more harm than the good they seek to achieve.
What does this mean in practical terms? States will always spy, but they should seek to do so in a way that protects, rather than violates, the fundamental rights of all people everywhere. In an era of artificial intelligence and big data, this is no easy task. But adopting a formal, normative approach to espionage is a moral and strategic imperative. Espionage, like other aspects of foreign policy, must be “values-based” if it is to succeed in countering threats to individual rights and the rule of law.