Since the start of U.S. military assistance to Ukraine in the wake of the Russian invasion, the United States has sought to walk a fine line between helping Ukraine to defend itself and provoking a broader war with Russia.
For this reason, the United States and the rest of NATO have refrained from engaging in direct military operations with Russian forces, opting instead for a strategy of providing substantial military assistance to Ukraine, largely though not exclusively in the form of weapons that would otherwise be unavailable to Ukrainian forces. Even here, the United States has chosen to provide weapons that are more defensive in character and suited for defending Ukrainian territory rather than other weapons that could allow Ukraine to strike deep inside Russia.
Last month, the United States proposed to provide Ukraine with advanced weaponry, including rocket systems with a range of nearly 50 miles, to continue its fight with Russia. These rockets are likely to be those fired by the Guided Multiple Launch Rocket System (GMLRS) and are GPS-enabled so that they can be aimed precisely at fixed geo-located targets. However, because rocket strikes into Russia 50 miles from the Russian-Ukraine border could be construed as non-defensive, the administration has obtained direct assurances from Ukrainian leaders that they would not use these rockets against targets within Russian territory.
Russian leaders may not take such promises at face value. But even if those promises are sincere and Ukraine has every intention of honoring them, it is still possible that in the heat of battle, these systems might still be used against such targets by mistake or inadvertence. Such an incident would be nearly impossible to walk back and thus could have grave consequences if Russian leaders did not believe Ukrainian assurances that they had not deliberately launched a strike on Russian soil.
The United States could significantly reduce the danger of an accidental incident by exploiting the GPS-enabled location awareness of the GMLRS system in question. In particular, it would be reasonably straightforward to construct a virtual geo-fence around Russia that would prevent the operation of the GMLRS system should anything inside Russian territory be targeted.
In other words, the GMLRS system could be programmed to operate only to hit targets that were not located inside Russia — if a system operator tried to enter the coordinates of a target within Russia, the system would provide a message noting the target is within a restricted zone and targeting would be refused.
The United States could implement this change to GMLRS software and inform Russia of the change. Russia would be unlikely to object. It might not believe U.S. assurances along these lines but if they did not, it would be no worse off than it would be if the United States did nothing to limit the GMLRS strike region. Ukraine would have no reason to object since it has already promised to obey the restriction.
The focus of this proposal is not GMLRS per se, though GMLRS is a good example. It could be used with any location-sensitive weaponry provided by the United States, from munitions to platforms such as helicopters or drones. This approach thus allows weapons with greater offensive potential to be provided to the Ukrainians while significantly reducing the risk that they might be used against targets in Russian territory. Disabling the geo-fence restrictions is possible in principle, but could only be accomplished with significant effort.
Using technological mechanisms to prevent attacking targets inside Russia with U.S.-provided weapons may have some value in reassuring Russia. But its greater value could well lie in making the United States — or any technologically advanced Western state — more willing to provide such weapons.
Of course, the utility of this approach is based on the assumption that concerns about escalation are genuine and not a smokescreen that conceals some other reason for not wanting to provide heavier weaponry to Ukraine. But if these concerns are indeed genuine, adoption of this or a similar technology-based approach may help the United States walk what is today a very fine line between helping Ukraine to defend itself and posing a direct military threat to Russia that could escalate uncontrollably.
Herbert Lin is a senior research scholar and Hank J. Holland Fellow at Stanford University. He served on President Obama’s 2016 Commission on Enhancing National Cybersecurity, is a 2019 fellow of the American Association for the Advancement of Science, served on the Aspen Commission on Information Disorder in 2020 and was a staff member for the House Armed Services Committee (1987-1990). He is the author of “Cyber Threats and Nuclear Weapons,” recently published by Stanford University Press.