In Pursuit of a Ceasefire in Ukraine: Lessons from Bosnia and Kosovo
By: Frederick Lorenz
Fast-moving international developments in February 2025 may soon create a real opportunity for ceasefire negotiations in the ongoing Ukraine war. After years of brutal conflict and significant changes in geopolitical trends, Ukraine and Russia are at a point where they may have no other choice but to agree that the war cannot go on. However, reaching an agreement will be only the first step. The real challenge lies in implementing a ceasefire that is both durable and enforceable. Key issues will include the separation of forces and defining the precise geographical boundaries of demilitarized zones, and establishing an effective international monitoring framework.
Historical examples of international peacekeeping efforts offer valuable insights for shaping such an agreement. The NATO-led missions in Bosnia and Kosovo in the aftermath of the Balkan conflicts provide instructive models, particularly in the crucial first ninety days of ceasefire enforcement. In both cases, military stabilization was assigned to a NATO force while a separate but connected civil administration worked to maintain governance and reconstruction.
By examining these past missions, policymakers can draw important lessons on force deployment, security arrangements, and international oversight mechanisms that could help stabilize Ukraine in the early stages of a ceasefire. While no single model is directly applicable to the complex and evolving situation in Ukraine, adapting elements from previous peacekeeping efforts could provide a viable framework for ensuring a cessation of hostilities and laying the groundwork for a more lasting resolution.
Establishing a Cease Fire Boundary Line and Zone of Separation in Ukraine
The situation in Ukraine is complex and unprecedented. Negotiations over the potential ceasefire line will be a formidable task as they may have a long-term impact on Ukraine’s outlook. In the short term, establishing effective mechanisms for separating opposing forces within a demilitarized zone can help prevent clashes and build stability.
The boundary readjustment and transition process followed in Bosnia could provide some lessons for Ukraine. Following the negotiation of the Dayton Accords in 1995, the General Framework for Peace (the General Framework) was signed later that same year, which established an Inter-Entity Boundary Line (Boundary Line) in Bosnia separating the conflicting parties and preventing further clashes. While the General Framework established a provisional Boundary Line, the parties themselves committed to establishing a joint commission with an equal number of representatives from both sides to develop a precise description of the Boundary Line. Disputed portions of the Boundary Line were further decided by arbitration.
Further, the General Framework declared a zone of separation spanning 2 kilometers on both sides of the Boundary Line making a zone 4 kilometers in total. The Boundary Line was established mostly along the military frontlines as they were at the time of the Dayton negotiations, with some major adjustments, most notably in the western part of the country, and in-and-around Sarajevo. The full separation of forces with a 4-kilometer distance between each other was fully completed ninety days after NATO forces operating as part of the Implementation Force (IFOR) tasked with implementing the Dayton Accords had taken over the authority from the UN forces previously responsible for enforcing peace in Bosnia.
In addition to a boundary readjustment, military forces and civilians in Bosnia were relocated according to the schedule contained in the General Framework. In fact, despite efforts to persuade them to stay, most Serbs (about 30,000) hastily moved to the Serb zone designated in the General Framework.
Following the example in Bosnia, a similar boundary line commission could be established in Ukraine to minimize subsequent clashes between Ukrainian and Russian forces caused by disputes over the precise definitions of the delineation line.
International Monitoring in Ukraine
The ceasefire and the established delineation line will also require a robust monitoring mechanism. While Bosnia’s IFOR and Kosovo’s KFOR forces had extensive mandates that included enforcement by NATO forces which are unlikely to happen in Ukraine’s case, certain aspects applicable to Ukraine can still be extracted.
For instance, the Bosnia context has shown that a centralized military control structure will be essential for Ukraine. Specifically, coordination in Bosnia was handicapped because the General Framework did not designate a single authority to synchronize the military, political, and humanitarian aspects of the NATO mission.
Additionally, a detailed report of the command and control arrangements in Bosnia found that the role of judge advocate officers was crucial and an important source of advice to commanders as they “played a key role in establishing [rules of engagement] for each force.” For instance, judge advocate officers would brief the IFOR Commander on rules of engagement and the Military Annex of the General Framework, including military activities such as defensive bunkers that would be permitted or prohibited in the zone of separation.
Moreover, new technologies are rapidly emerging that can help manage or enforce peace and inhibit the deterioration of crises into war. Data collected through sensor and surveillance systems can help increase the confidence of the parties to an agreement and provide operational intelligence for preventing violence. Autonomous unarmed drones could play a role in monitoring lines of contact and ceasefire violations to reduce the risk to peacekeepers on the ground.
Since technology collects a tremendous amount of information, Artificial Intelligence (AI) could help monitoring missions review the images of potential violations and the interface with satellite imagery. AI can provide advantages but also risks from intentional disinformation from parties to the conflict. But even with useful information, there needs to be effective mechanisms for command, control, and enforcement of provisions in the ceasefire agreement.
In this regard and given President Trump's calls for European commitment, Europe will likely have to bear the main burden of providing security and ensuring compliance with a ceasefire agreement in Ukraine. Nonetheless, as highlighted in a recent paper by the German Institution for Security Affairs (SWP): “A mission entirely without U.S. support is inconceivable because of the mix of capabilities required for such an endeavor.”
As regards the size of the possible European force in Ukraine, President Zelenskyy has stated that 200,000 peacekeepers would be needed. For comparison, the KFOR mission in Kosovo began in 1999 with 48,000 soldiers, which covers almost 11,000 square km. Ukraine is almost 55 times larger. Realistically, without the US, even the 200,000 peacekeeper number is unlikely to be feasible. Nevertheless, with the proper technological support, a much smaller force might be able to effectively cover a Ukraine demilitarized zone.
Eli Tenenbaum, director of the Security Studies Center at the French Institute of International Relations, offers details on how such a smaller force could look like. He proposes deploying “three to five brigades with a total of about 40,000 troops with robust air defense capabilities, positioning these forces 20-50 kilometers from the frontline, east of the Dnipro River.”
Additionally, it will take some time to identify, assemble, and properly deploy to the region. In Bosnia, a large part of IFOR was already in the country as part of the UNPROFOR, and in Kosovo, the NATO forces were in the region and could deploy along previously established ground routes. In Ukraine, the differences are vast, both in terms of the size of the armed conflict zone and the distances to move and properly deploy. Although the US will likely not have “boots on the ground,” it may very well be able to supply intelligence, logistic support, and strategic airlift for the multinational force.
Negotiating a ceasefire
Undeniably, before thinking about implementing a ceasefire in Ukraine, the parties will need to agree to this ceasefire.
The Public International Law and Policy Group (PILPG) provides valuable resources to support negotiations, including a Ceasefire Drafters Handbook. Several core elements are listed from a comparative analysis of ceasefires: (1) a cessation of hostilities, (2) the separation of forces, and (3) the verification, supervision, and monitoring of the agreement.
Past agreements and efforts to establish peace between Ukraine and Russia further provide important insights and words of warning for current attempts to develop an effective ceasefire or peace agreement. Another PILPG document outlines the substance and several key failings of recent past agreements, including the
Budapest Memorandum, Minsk I and II. This information should be crucial for those attempting to negotiate a durable cessation of hostilities in Ukraine.
For Ukraine, the initial process could start and conclude rather quickly, and the written agreement could be only a few pages long. The Gaza agreement was only 1,400 words. The agreement consists of three related and interconnected stages, each with a forty-three-day schedule, and a description of the conditions (including the release of detainees) to be met by each side.
The initial ceasefire arrangement in Ukraine might similarly consist of three stages of about 45 days each. Phase 1 could commence after an agreement for cessation of hostilities, and during that time, the preliminary boundary lines would be established, and remote monitoring would begin. Phase 2 could provide a deadline for the withdrawal of the military forces of Russia and Ukraine from the newly established zone of separation. Phase 3 could provide for the deployment of the multinational force and the commencement of monitoring and other activities described in the ceasefire agreement.
For a ceasefire agreement in Ukraine, the first or second phase will likely require a withdrawal of Ukrainian forces from Russia in the Kursk Region, with a corresponding Russian yielding of claims to certain areas that it has previously “annexed” but does not physically control. This may have to wait until a more permanent peace agreement is signed. A boundary commission, like the one used in Bosnia, may be essential in the short term. The difficult part of the ceasefire negotiation will be the establishment of an organizational framework that includes military, civilian, and humanitarian tasks, as well as a reconstruction plan. While not discussed in this blog, long-term security guarantees will be another highly challenging negotiation conundrum.
Conclusion
A ceasefire agreement in Ukraine will require careful negotiation and the development of an innovative political-military framework for peace. The structure of the framework and its implementation will likely be the responsibility of the major European powers. Although there is no single model that is directly applicable, negotiators can draw on successful aspects of previous models, including NATO IFOR, and UNMIK KFOR, among others. Designation of boundaries, separation of forces, verification, and monitoring of zones will be critical in the short term. New technologies may provide options that were not
available in previous conflict areas. Ukraine is unique and challenging with multiple factors that might prevent permanent peace. However, a well-drafted ceasefire agreement can play a critical role in establishing a durable cessation of war.