Abstract
Espionage remains arguably one of the most contentious and least regulated aspect of international relations. Despite being a common practice among states, especially in the contemporary age of sophisticated technology and global interconnectedness, espionage occupies a legal gray area under international law. This paper critically examines the legality of espionage, with a focus on its vagueness during peacetime and its clear regulation during armed conflict. Under the Geneva Conventions, wartime espionage is addressed to a certain degree, defining the status of spies and the punishment they face after capture. However, there is no universal legal instrument under international law that requires prohibition or justification of espionage during peace times. 
The study analyzes how espionage is likely to conflict with fundamental principles of international law, such as sovereignty, territorial integrity, and non-intervention. Yet, due to its reciprocal nature and strategic importance, states continue to be engaged in and tolerant of espionage, creating a paradox between political practice and Legal norms. Cases such as the Lotus Case (France v Turkey), interpretations of the Vienna Convention on Diplomatic Relations, and insights from the Tallinn Manual on cyber operations shed light on the boundaries however blurred within which espionage operates.
Furthermore, the paper considers how domestic legal mechanisms criminalize espionage to serve national interests, while international law is largely silent. By exploring the tensions between state behavior and the normative framework of international law, this paper concludes that espionage, though widely practiced and politically accepted, urgently requires more coherent and consistent legal treatment at the international level.

Introduction:
Often referred to as the ‘World’s second oldest profession’¹  Espionage has been the central feature of international relations. It dates back to the ancient empires where sovereign states relied on covert operatives to gain an edge in times of both War and Peace. In Ancient China, Sun Tzu devoted an entire chapter in his book ‘The Art of War’ to the use of spies and how proper intelligence could ensure victory without fighting.²  In Roman Empire Julius Caesar, during his Gallic wars used the intelligence-gathering abilities of his army to an extent never seen in Roman History.³
Espionage is generally defined as the act of spying or using spies, agents, assets, and intelligence officers, as well as technology, to collect secret information, usually through illegal means.⁴  Despite its long and Universal presence in global politics, espionage remains highly under-regulated in international law, with no comprehensive legal framework governing its practice.
Unlike Acts of aggression (i.e. Violation of the UN Charter) or Treaty violations (i.e. Violation of the Vienna convention on Laws of Treaties), Espionage exists in the gray zone. It is neither explicitly permitted nor categorically prohibited by International Law. 
States across the world routinely engage in intelligence gathering.⁵  It is sometimes to protect National Security (e.g.: Soviet spies penetrated the Manhattan project at Los Alamos and several other locations, sending critical information back to Russia that helped speed the development of soviet bomb.⁶ It helped in Balancing the Power in world after the Second World War), Sometimes to assess the strategic posture of adversaries (During the Cuban Missile Crisis, the United States used aerial reconnaissance (U-2 spy plane) to photograph soviet missile installations in Cuba.⁷  It was crucial in revealing the presence of nuclear missiles just 90 miles from American shores), and at times even to monitor their allies (During the Gene Cold War, the United States monitored France, an ally due to concerns over France’s nuclear program and its independent foreign policy under Charles de Gaulle). 
The complexity of espionage in international law becomes more pronounced when distinguishing between Wartime and Peacetime Espionage. 
During Armed Conflict, the law provides clearer definitions and consequences for acts of espionage, particularly under the Geneva Conventions and Customary International Humanitarian Law. Peacetime espionage, by contrast, resides in gray zone- largely ungoverned by binding International Treaties and instead shaped by shifting norms, state practice and domestic legal frameworks. 

Espionage During the Wartime:
The legal effects of espionage are clear particularly under the Geneva Conventions and their Additional protocols during wartime. 
According to the Lieber code (Article 88), the Brussels Declaration (Article 19) and the Hague Regulations (Article 29), Espionage is defined as 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.
Importantly, not all Intelligence-gathering activities qualify as espionage under IHL. For instances, 
1.    Soldiers wearing uniforms of their armed forces while collecting information behind enemy lines are not considered spies. ⁸
2.    A soldier resident of territory occupied by an adverse party and who on behalf of the party gathers or attempts to gather information of military value shall not be considered doing espionage unless he does so through an act of false pretenses or deliberately in a clandestine manner. ⁹
3.    A soldier not a resident of territory occupied by an adverse party engaged in espionage may not be treated as a spy unless he is captured before he rejoins the armed forces to which he belongs. ¹⁰
The critical factors that distinguish espionage from lawful reconnaissance are clandestinity, false pretenses, and the intention to aid an enemy party. 
Legal consequences: 
Spies, under IHL, are classified as Unlawful combatants. As a result, they are not entitled to prisoner of war (POW) status if captured during their covert operations.¹¹  This classification removes the protections generally afforded to combatants under the Geneva Conventions, such as Humane Treatment, Accommodation, Medical care, Communication Rights and so on.¹²
However, IHL also imposes certain limitations on how spies are treated upon capture. While they may be prosecuted and punished for their actions, summary execution is prohibited.¹³  Captured spies are entitled to a fair trial, and if they are able to rejoin their armed forces before capture, they may no longer be prosecuted for their previous acts of espionage and must be treated as regular prisoner of War (POWs).¹⁴
One Famous case example was of ‘Francis Gary Powers’ a US pilot captured by the Soviet Union in 1960 while flying a U-2 spy plane, exemplifies the intersection of military reconnaissance and espionage, although the legality of such aerial surveillance remained outside the formal scope of IHL at the time. Later, he was released by the Soviets as a part of a spy swap (i.e. traded for Rudolf Abel a Soviet spy) between the United States and the Soviet Union in Berlin. 
In modern, times, with advancements in technology, espionage during armed conflict has expanded to include cyber operations and satellite surveillance further complicating the distinction between legal reconnaissance and unlawful spying. 

Espionage during Peacetime: 
Unlike in Wartime, when espionage is partially regulated under international humanitarian law, peacetime espionage exists in a legal limbo under international law. There is neither a treaty nor a customary international law that explicitly prohibits or legitimizes intelligence gathering activities carried out during peacetime. 
This silence in law does not imply acceptance or illegality but it rather reflects a pragmatic reluctance among states to codify norms for a practice in which they routinely engage. 
International law traditionally deals with state sovereignty, non-intervention and peaceful coexistence, but espionage challenges their principles. For instance, sending covert agents or incepting confidential communications arguably infringes upon the territorial sovereignty of the target state. However, given the widespread and reciprocal nature of espionage, states have refrained from establishing definitive legal rules. 

Judicial perspective and Scholars on peacetime Espionage:
In Lotus Case (1927), the Permanent Court of International Justice held that “restrictions upon the independence of states cannot be presumed” and the International law leaves to states “a wide measure of discretion which is only limited in certain cases prohibitive rules”, this suggest that acts not expressly prohibited under international law remain legally permissible.¹⁵  This gives a legal loophole to extend the logic to peacetime espionage, arguing that in the absence of explicit prohibitions, espionage is not unlawful justifying the argument ad hominem of “tu quoaue” i.e. you as well.
There is also a huge faction among the scholars: 
Permissivists argue espionage functions within a lotus vacuum, one in which states may spy on each other and on each other’s nationals within no restrictions, justifying their behavior through the argumentum ad hominem of “tu quoque”.¹⁶  
Prohibitionists have launched a quest to find such expressive constraints within the lex lata, citing as potential candidates rules surrounding territorial integrity; sovereign equality; non-intervention, principles concerning friendly relations and cooperation among states; the inviolability of diplomatic and consular communications; state immunity and state ownership rights over certain types of property; States good faith obligations and obligations to settle disputes through peaceful means; the international protection of trade secrets and intellectual property; certain regulations on the use of the global commons (the waters, airspace, outer space, and cyberspace); international telecommunications law; and the international human rights to privacy.¹⁷
However, this quest has so far been futile as prohibitionist scholars refuse to come to grips with the insurmountable realization that nation-states have simply accepted, either openly or tacitly the prevalence and importance of peacetime espionage as a necessary tool in international affairs.¹⁸
 
Espionage by non-state actors and professionals: 
The challenge in regulating peacetime espionage is the diversity of actors involved. Modern Intelligence collection is no longer limited to state agents or military officers. Diplomats, Journalists, businesspersons, and even academics may become unwitting or deliberate channels of intelligence collection. For instance, diplomatic espionage where officials gather intelligence under the cover of diplomatic immunity is both common and controversial. 
Under the Vienna Convention on Diplomatic Relations (VCDR)¹⁹  and the Vienna Convention on Consular Relations (VCCR)²⁰  State can use Persona Non Grata for such Diplomats.
However, Journalistic whistleblowing or leaking of sensitive information may be labeled as espionage under domestic law but is defended under International Standards of press freedom and government transparency. ²¹

International and Domestic Espionage Law: 
International Framework: 
On the International level, the law of espionage remains scattered and Indirect in both War and Peace times. There is no comprehensive international treaty precisely governing espionage during peacetime or wartime. Instead, its legal treatment is inferred by implication from other field of law, such as International Humanitarian Law (IHL), International Human Rights law, the law of Diplomatic relations, and the law on the use of force. 
During wartime, Espionage has been addressed by Article 46 of the Additional Protocol I of the Geneva Conventions, which distinguishes between legitimate and illegitimate collection of intelligence and where they should be granted Prisoners of war status (POWs) and when exactly one should not be engaging in that practice.
Outside the realm of armed conflict, Espionage may violate international norms such as sovereignty²², non-intervention²³, and the inviolability of diplomatic missions under the Vienna convention on Diplomatic Relations (1961)²⁴  and the Vienna convention on Consular Relations (1963)²⁵.  The Tallinn Manual has included, that the premise of diplomatic mission or consular post may not be used to engage in cyber activities that are incompatible with diplomatic or consular functions.²⁶  Also, Diplomatic agents and consular officials may not engage in cyber activities that interfere with the internal affairs of the receiving state or are incompatible with the laws and regulations of that state.²⁷ Nevertheless, satellite surveillance and open-source intelligence gathering are generally considered permissible, often justified under principles such as the peaceful use of outer space.²⁸
The Tallinn Manual²⁹  applies to peacetime cyber espionage stating “although peacetime cyber espionage by States does not per se violate international law, the method by which it is carried out might do so”. It also adds that cyber espionage, while potentially violating sovereignty or the principle of non-intervention, does not inherently breach international law unless it includes coercive elements. 

Domestic legal framework: 
While there is the gray area in international law, the domestic legal system has taken a more assortative role, criminalizing unauthorized access to state secrets and regulating intelligence activity. 
One prominent example is the ‘United States Espionage Act of 1917’, which penalize the disclosure or transmission of the National defense information to foreign entities. This law has been used in high-profile cases such as the Rosenberg Trial (1951) and the Edward Snowden’s Indictment (2013) for leaking classified NSA documents. The Foreign Intelligence Surveillance Act (FISA) further authorizes surveillance of foreign agents and governments under judicial oversight.
Similarly, China, Russia and other major powers have adopted strict laws that punish espionage and economic spying, particularly in the fields of cyber technology, defense and foreign affairs. 
In Nepal, the National Penal Code 2017, in particular, contains sections that criminalize the act of providing confidential or classified information to foreign actors or working as an agent of a foreign intelligence service. 
The National Penal Code (2017) Section 56 has provisions for espionage where, a Person with intent to undermine the sovereignty, security or geographical or territorial integrity of Nepal or to Prejudice the interests of Nepal or with the knowledge that such consequences are likely, or being induced by any foreign country or international organization, supply to any one any information relating to the military situation, strategic arrangement or internal security of Nepal or relating to any matter that must be kept confidential by the Government of Nepal from the political, economic or diplomatic viewpoint or confidential document, or any matter that is confidential or must be kept confidential under law or conspire or attempt to commit, or abet the commission of, such act or do any other act with intent to supply such information, and a person who commits such act shall be considered to have committed espionage.³⁰
Punishments are as follows: 
1.    Espionage about matters of military situation, strategic arrangement or internal security of Nepal. Sentence of Imprisonment for a term not exceeding 25 years.
2.    Espionage in relation to matter that must be kept confidential by the Government of Nepal from the political, economic or diplomatic viewpoint or any other confidential document. Sentence of Imprisonment for a term ranging from 5 years to 10 years. 
3.    Espionage to any matter other than mentioned above. Sentence of imprisonment for a term not exceeding 5 years and fine of 50 thousand rupees. 
4.    Person despite the knowledge that anyone is going to commit espionage, does not give information thereof to the Government of Nepal. Sentence of Imprisonment for a term not exceeding 1 year and a fine of 1,00,000 NPR. 


While Nepal does not possess a specialized legal framework for intelligence operations, espionage is implicitly governed by provisions related to treason, National security, and State Secrets. Additionally, the National Investigation Department (Rashtriya Anusandhan Bibhag) operates under the Office of Prime Minister and Council of Ministers, conducting both domestic and limited foreign intelligence functions although its scope, methods, and oversight mechanisms are opaque and largely undocumented in the public domain. ³¹
There have also been instances of alleged foreign surveillance and Intelligence activities within Nepal, especially given its strategic location between India and China. Some of the examples are: During the1950s and 1960s, the CIA trained Tibetan guerrillas, known as Chushi Gangdruk, to fight against Chinese forces and the operations were conducted in the Mustang region of Nepal shows the CIA foot prints in Nepal.³² KGB operations in Nepal were on various dimensions. It worked closely with Nepal communist parties and other leftist groups to promote soviet policies and Ideology, conducted surveillance of US and Western diplomats in Nepal, provided scholarships to Nepalese students who were often recruited by the KGB to act as informants or agents upon their return.³³ There is also a heavy influence of various agencies like: ISIS, RAW, MSS, MI6, and Mossad because of Nepal’s unique geopolitical location. Nepal has become Agentsumpf (“Agent Swamp”) same as the Berlin during the time of the Cold War. These activities pose a serious security threat not only for Nepal but the embassies of other countries that are in Nepal. To tackle this problem renewed calls for clear legislation and policy oversight in Nepal’s intelligence architecture, especially in an era where cyberespionage and digital surveillance are increasingly prevalent. 

Conclusion: 
Espionage remains a complex and paradoxical element of international relations simultaneously condemned and practiced by nearly all states. Despite being omnipresent in global statecraft, there exists no comprehensive international legal framework that categorically regulates or prohibits espionage, especially during peacetime. 
While International Humanitarian law offers limited guidance on wartime espionage particularly regarding the treatment of captured spies the same cannot be said for peacetime activities, which continues to reside in a gray zone of legality being shaped by state practice and political tolerance than by enforceable legal norms. 
The reality is that espionage is an “open secret” in international affairs. States often justify their intelligence operations based on National security, Strategic necessity, and the Right to self-defense. These justifications are further emboldened by the absence of clear legal prohibitions and the difficulty of attribution, especially in the age of cyberespionage and remote surveillance technologies. 
While espionage may infringe on principles like sovereignty, non-intervention, or the inviolability of diplomatic premises, the lack of consistent enforcement mechanism at the international level leaves states largely free to engage in such conduct provided they can avoid diplomatic fallout. In this sense, espionage reflects the ‘realpolitik’ nature of international relations, where the power and the Interest of the States often override legal and ethical concerns. 
Domestically most states including Nepal have developed some legal tools to criminalize espionage within their jurisdictions and to protect states secrets. However, the lack of transparency, accountability and legal clarity surrounding intelligence agencies operations remains a challenge, especially in emerging democracies. 
As technology evolves the boundary between war and peace continues to blur with Hybrid warfare (i.e. tactics used by states which is a blend of conventional military force with cyberattacks, disinformation campaigns, economic coercion and support of proxy groups to weaken the adversaries without declaring the formal war). The need for a clear international dialogue on the legal regulation of espionage becomes increasingly urgent. Until then, Espionage will likely remain a legally ambiguous but politically accepted tool of statecraft, woven into the fabric of both international diplomacy and National Defense.