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How Does International Law Apply to the Chinese Balloon?, Vol. 56.1

Nicholas Moran


24 Aug 2023


Sooty piles of gray stone rose into an overcast gray sky. One could barely distinguish the two grays. Neon vests shone sharply against the gray, worn on workers scurrying about the hard-rock mines of Montana’s hill country. Miner Michael Alverson’s gaze drifted to the sky and noticed the moon. Soon another moon grew apparent “off to the right.” Confused, Alverson gathered coworkers and observed the false moon through binoculars. “It just kind of… seemed like it had a comet trail or tail, and then it just, like, totally stopped and just started hovering,” recalled Alverson. Quickly the truth dawned upon him, “it appeared to be some sort of balloon.

This second moon looming over Montana’s mining hills embroiled the United States in a multi-week crisis with the People’s Republic of China. Verbose American accusations, indignant Chinese denials, bellicose newspaper headlines, rabid talking heads, scrambled fighter jets, and, ultimately, the U.S. Air Force shooting the balloon down into the waters of the South Carolina coast. “It was two fighter jets dancing with this thing going around and around it,” eyewitness Jeffrey Billie told the New York Times, “then… the round big white ball that we saw all of the sudden looked like a shriveled Kleenex” falling into the Atlantic.

The Sides’ Arguments

Both the United States and China invoked international law in their condemnation of the other. The United States callously destroyed a peaceful weather balloon, and illegally refused to return the wreckage, claimed China. “Immature and irresponsible-indeed hysterical” behavior on the Americans’ behalf. Conversely, the United States accused a belligerent China of ignoring American sovereignty over its airspace, a sovereignty codified in international law. Thus, President Biden’s decision to destroy the balloon was both prudent and illegal, ridding American airspace of a hostile intelligence gathering device.

Who is correct? Debates amongst international-law scholars have littered American newspapers, but the discussions have formed a consensus which I will explore further in this forum post.

Scholars Weigh In: Chicago Agreement

Most scholars affirm the United States’ position, arguing it rests on solid footing within international law. The world’s governments met in 1944 at Chicago’s Stevens Hotel’s grand ballroom, negotiating an international legal framework for airspace under glistening, brass chandeliers. The discussions birthed the Convention on International Civil Aviation (ICAO Convention), of which both the United States and the People’s Republic of China are signatories.

The ICAO Convention established that every nation enjoys “complete and exclusive sovereignty over the airspace above its territory,which typically is understood as the maximum altitude of aircraft (roughly 45,000 to 60,000 feet above sea level, thus not including satellites). Thus, should an aircraft enter the airspace, particularly unmanned aircraft, the sovereign may ground the aircraft.

Therefore, the downing’s legality hinges on whether the balloon is an “aircraft” under the ICAO Convention. There is a long history of considering balloons to be “aircrafts” in the context of the ICAO. The United Nations itself deems balloons to be “non-power-driven, unmanned, lighter-than-air aircraft in free flight,” thus using the magic word “aircraft.” Major powers such as the United Kingdom, Japan, and the Soviet Union have invoked this power to down balloons throughout the 20th Century. Therefore, adopting the Chinese argument would abandon decades of practice in regulating sovereigns’ airspace. 

Scholars Weigh In: Montreal Agreement

The Chinese raise additional concerns that downing the aircraft was particularly cruel due to its alleged civilian nature and invoked international protections that apply to civilian aircraft. Why destroy a research balloon gathering meteorological data to better our understanding of weather balloons? Whether the balloon was a research or reconnaissance balloon, its unmanned nature puts it outside the protections carved out for civilian aircraft. 

The United Nations amended the ICAO in Montreal in 1984, seeking to protect civilian aircrafts from violent shootdowns. Civilian aircrafts peacefully passing across international borders are vital for global prosperity. Violent, deadly downings risk chilling important exchanges, argued diplomats in Montreal. Thus, they agreed to discourage downings when such operations would imperil “the safety and the lives of persons.” No one was aboard the Chinese balloon, nor were people aboard past balloons legally downed by major powers. Therefore, the Montreal protections do not apply to the Chinese balloon. 

Project Loon: A Potential Framework 

While the Chinese balloon may have served nefarious intelligence purposes, there still is a need for an efficient framework for managing balloons that cross international borders. Google’s Project Loon forced the UN’s ICAO to craft such a framework in 2018 at Punta Cana, Dominican Republic.  Google planned to launch balloons into the stratosphere, beaming internet signals to remote, impoverished, or disaster-stricken locations across the globe. Thus, the project by its very nature necessitated high-altitude balloons crossing quite a few international borders.

The Punta Cana negotiations birthed several guidelines for how to legally operate balloons that pass through international airspaces. For starters, there is a general duty for a sovereign to ensure their balloons are “effectively” operated, invalidating runaway balloon or rogue operator defenses. Authorities also ought to notify any impacted air-traffic-control services to “minimize hazards to persons, property or other aircraft.” If a sovereign denies the balloon entry but entry into the sovereign’s airspace proves inevitable, the operator must end the balloon’s operations immediately.

Such a model would allow sovereigns to protect their airspaces from unwanted activity while encouraging productive uses of balloons drifting across international borders. Future confused episodes could result in saved equipment and the continuance of productive activities, presuming the questioned activities truly were not intelligence-gathering upon a foreign power.


Costly, precious equipment fell shattered into the waters off South Carolina’s coast. Whether the balloon’s function was reconnaissance or meteorology, the United States’ response is in compliance with the governing international legal standard. The IAOC authorizes sovereigns like the United States to shoot down unmanned aircraft such as balloons, should they enter within American airspace without the sovereign’s consent. The United Nations further fine-tuned this balloon standard through its governance regarding Google’s Project Loon, which seems to be a workable framework to balance the interests of peaceful aviators and sovereigns. Therefore, on strictly legal grounds, President Biden’s decision to down the Chinese balloon is justified.