The Yugoslav Partisan War

A country, but not yet a common political community

The invasion of 6 April 1941 did not simply destroy a stable nation-state from outside. The Kingdom of Yugoslavia had been formed in 1918 by joining Serbia and Montenegro with the South Slav territories of the former Austro-Hungarian Empire. It was multiethnic and multiconfessional, yet its state institutions and army remained centered on the Serbian dynasty and bureaucracy. The centralized constitution of 1921 was understood by many Serbs as protection for unity, but experienced by many Croats and Slovenes as Serbian hegemony. When King Alexander I dissolved parliament and renamed the country Yugoslavia in the 6 January Dictatorship of 1929, repression of party politics did not remove the national conflict. After the king's assassination in 1934, Prince Paul ruled for the underage Peter II. The regency managed competing interests from above, but did not create a wider social agreement.

The Cvetković–Maček Agreement of 26 August 1939 temporarily patched the crisis. The government and Vladko Maček, leader of the Croatian Peasant Party, created an autonomous Banovina of Croatia. It did not settle the division of Bosnia and Herzegovina or the status of Serb communities inside the new unit. Croatian nationalists considered it insufficient, centralist Serb forces considered it a concession, and the Ustaše attacked it as a betrayal of the cause of an independent Croatia. The country was also a poor predominantly agrarian society, with sharply unequal literacy and industrial development across its regions. These conditions made people's experience of the state diverge. “Defending Yugoslavia” therefore did not carry one identical political meaning for everyone.

International pressure intensified these fractures. During the late 1930s Germany drew Yugoslav trade and raw-material exports into its orbit, while German and Italian expansion threatened the kingdom's borders. After Italy's failed attack on Greece, Germany needed to move through the Balkans to attack Greece itself. Prince Paul's government joined the Tripartite Pact on 25 March 1941 and granted transit rights, but a coup on 27 March, amid opposition from Serbian officers and much of the public, declared Peter II of age and installed a government headed by Dušan Simović. When the new government sought to reconsider the pact, Hitler treated the move as hostility and ordered Yugoslavia destroyed as a state. The Communist Party had been illegal since 1921, but a small nationwide underground organization under Josip Broz Tito had survived. Before the invasion, forces claiming royal legitimacy, national autonomy, and class emancipation already offered competing answers. Once foreign armies crossed the borders, the central question became who would organize the space left by the state's collapse, and what Yugoslavia would be rebuilt.

From a surrendered kingdom to an organized rising

The collapse of April 1941 was more than a lost military campaign. After officers overthrew the pro-Axis government on March 27, Adolf Hitler ordered Yugoslavia not merely to be defeated but to be destroyed as a state. Bombing and invasion began on April 6, and in little more than ten days the kingdom capitulated. After the unconditional surrender of April 17, its borders were cut according to the occupiers' convenience. Germany directly ruled most of Serbia and annexed northern Slovenia; Italy, Hungary, and Bulgaria also took Yugoslav territory. Germany sponsored the Ustasha regime, the Independent State of Croatia, over Croatia and most of Bosnia. The kingdom's collapse removed the weak central authority that had held several peoples within one state and brought occupation, collaborationist governments, and militia violence into everyday life.

Under these conditions, the Communist Party of Yugoslavia did not immediately begin an open rising. It was an illegal organization, and while the German-Soviet Molotov-Ribbentrop Pact remained in force, the line of the international communist movement also called for avoiding direct conflict with Germany. After the invasion, the party leadership worked from Zagreb and Belgrade to preserve its contacts, safe houses, and weapons. This was not simply passivity. It was a calculation that survival was necessary if a nationwide organization was to act. That calculation changed on June 22, when Germany invaded the Soviet Union. The Comintern's direction required communist parties to turn the defense of the Soviet Union into an anti-fascist struggle in their own countries.

The change appeared not only in slogans but in people and places. On June 22, about forty Croatian communists entered the Brezovica woods near Sisak and formed the 1st Sisak Partisan Detachment. From the next day, this small unit was assigned to disrupt railways and communications and connect party organization with the countryside. It was not yet an army, and the danger of collective reprisals was severe, but an underground cadre had become an armed political unit. This was why Tito's leadership could formalize a nationwide rising on July 4. The Partisans did not begin as a spontaneous expression of national anger after surrender. They began when an underground organization, preserved amid occupation and violence, used the international turn to prepare armed resistance together with a new political order.

Why the uprising began to look like a state in Užice

The decision taken by the Communist Party's Political Bureau in Belgrade on 4 July 1941 was more practical than symbolic. It sought to exploit Germany's redeployment to the Soviet front by cutting occupation railways and communications, joining scattered armed groups into Partisan detachments, and widening the revolt across the country. The balance of forces was desperate. German troops were joined by Italian, Bulgarian and Hungarian units and forces of collaborationist regimes, amounting to roughly 400,000 men in the occupied territories. The Party leadership therefore did not expect to win a conventional war. Its calculation was to use mountains and underground organization to raise the cost of occupation, while building both military strength and political confidence in liberated areas. Later official histories described this as a united front for national and social liberation, but royalists saw the same policy as a premature adventure. For the Chetniks led by Draža Mihailović, the first task was to preserve forces for the restoration of the monarchy after the war. Immediate Partisan attacks, they argued, risked making civilians pay for German reprisals. The disagreement soon became an armed contest. When German forces attacked western Serbia from September, the two movements sometimes fought in the same area, but competed over who would govern liberated territory and mobilize its inhabitants. After Partisans took Užice on 24 September, they tried to create a functioning rear, not merely a refuge for retreating fighters. People’s Liberation Committees administered the area, factories and workshops stopped by the war resumed production, and about 145 kilometres of railway and a postal service were operated. A factory installed in the vaults of the Užice bank produced 16,500 rifles and 2.5 million rounds of ammunition. The newspaper Borba announced not only military orders but the social claim of the new authority. This ‘republic’ was not a stable state. Sources disagree substantially about its population and boundaries, while the territory had to absorb the demands of weapons, food and refugees. The occupiers made the social cost catastrophic through village burnings and hostage executions. Following Hitler’s instruction of 16 September, the German command ordered the revolt crushed ‘in the shortest possible time’ and prescribed the execution of 50 to 100 hostages for every German soldier killed. When the November offensive began, the workers’ battalion defending Užice suffered heavy losses at Kadinjača, and the Supreme Headquarters withdrew toward Sandžak. Yet this was not simply the disappearance of a liberated zone. At the Stolice meeting on 26 September, the Partisans decided to standardize detachments and commands and to expand mobilization through People’s Liberation Committees. The lesson of Užice was that an army could not survive by holding territory alone. Even in retreat it had to carry its fighters, production, administration, and a political legitimacy distinct from the restoration of the monarchy.

Who could speak for Yugoslavia in the name of resistance?

The clash between the Partisans and the Chetniks in the autumn of 1941 was not simply a contest over command. The two movements defined the timing and subject of liberation differently. Josip Broz Tito’s Communist Party believed that the political vacuum created by occupation had to be filled immediately. Weapons could not remain the private property of individuals or local commanders. They had to be placed under people’s liberation committees and a military chain of command, so that the movement could withstand reprisals and bring not only Serbs but also Croats, Bosnian Muslims, and Slovenes into a common struggle. Draža Mihailović’s royalist movement, by contrast, argued that the legitimacy of the king and the government-in-exile remained alive. For the Chetniks, a mass rising risked turning German reprisals against civilians and handing the postwar political settlement to the Communist Party. A Yugoslav embassy account submitted to the US State Department in 1943 presented this position as a war for “national freedom” and “a free, democratic and reconstructed Yugoslavia,” grounded in loyalty to the king. This was why the Chetniks understood themselves not as a Serbian militia but as the successor to the Yugoslav army.

Yet the two calculations destroyed each other inside the same occupation regime. When negotiations failed and armed clashes broke out around Ravna Gora and western Serbia in November 1941, some Chetnik commanders came to see the Partisans as the enemy that had to be eliminated first. Some made local arrangements with German forces, the Nedić administration, or Italian troops in order to preserve their units. This does not mean that every Chetnik was a collaborator from the outset. The royalist policy of preserving strength persuaded people because, amid massacres and hostage executions, it presented itself as a defensive plan for keeping villages alive. But that choice gave the Partisans a decisive political weapon. They defined not only the occupiers and their auxiliaries but also forces awaiting a royal restoration as competitors for the postwar order, and built administration and armed struggle inside the same organization.

The result was the AVNOJ session held at Bihać on 26 November 1942. It was not a parliament announcing victory, but an institution testing its claim to representation while no recognized national state operated on the ground. Delegates were allocated among Bosnia and Herzegovina, Croatia, Serbia, Montenegro, Slovenia, Sandžak, and Vojvodina to give the body a pan-Yugoslav character. Macedonia had no representative, and several delegates failed to arrive. Rather than simply conceal these defects, AVNOJ tried to answer practical questions through its connection with the land councils and people’s liberation committees: who would collect resources, distribute food, administer justice, and supply the army? Its chair, Ivan Ribar, had a career connected to the constitutional assembly of the prewar kingdom. The participation of vice-president Nurija Pozderac also made visible the claim that this was not merely a Serbian or Communist institution.

Tito nevertheless did not call AVNOJ a government. Moscow and the Comintern urged the Partisans not to confront the London-backed government-in-exile directly, but to widen the coalition under an anti-fascist, pan-Yugoslav form. Bihać therefore did not yet proclaim the immediate abolition of the monarchy. It adopted a multi-ethnic federation as the principle of the future state and connected the administration of liberated territory to a national political authority. That indirection was also its strength. While the government in London claimed constitutional legitimacy, AVNOJ organized food, manpower, security, and punishment in the territory where the war was actually being fought. Civil war imposed a terrible cost on the Partisans, but it also opened the institutional space in which an army of resistance became a body claiming to represent a state.

The army that survived encirclement refused to abandon its wounded

The two great offensives of 1943 proved not that the Partisans could hold every liberated territory, but that they could remain an army after encirclement. Operation Weiss, begun on 20 January, brought roughly 90,000 German troops, reinforced by Italian formations and Chetnik auxiliaries, against western Bosnia in an attempt to destroy the Bihać liberated zone and the Supreme Headquarters. The Partisans answered by moving their main force and central hospital eastward rather than defending territory at any price. This was not merely a retreat. The hospital held thousands who could not fight. Leaving them meant surrendering them to Axis execution or reprisals by collaborationist forces. After taking Prozor and destroying the bridges over the Neretva, the Partisans made the enemy misread their direction, then improvised a crossing and carried the wounded and the main force across. The March breakthrough was therefore not a battlefield victory in the simple sense. It was an operational survival that preserved both the command and the hospital the Axis had intended to eliminate. The cost was severe: fighters died in battle and on the march, while hunger, disease, cold, air attacks, and the flight of civilians added to the losses. Yet refusing to abandon the hospital was also a political and military choice. It preserved experienced personnel and the confidence on which a mobile revolutionary army depended, rather than treating wounded people as disposable material.

Operation Schwarz began on 15 May. Germany, Italy, Bulgaria, the Croatian state, and supporting forces committed about 127,000 troops and more than 300 aircraft. Around Sutjeska the Partisans had roughly 22,000 soldiers, while the central hospital contained about 3,000 wounded. Hunger, typhus, and shortages made the encirclement worse. After an attempt to break toward Foča failed, the Supreme Headquarters shifted toward the Piva and Sutjeska valleys. In the breakthrough during early June, three brigades and more than 2,000 wounded, together with largely unarmed medical staff, remained inside the ring, and many were captured and killed. Sutjeska cannot therefore be reduced to an inexpensive heroic legend. The Partisans did not save the whole hospital and lost a large part of their force. Nevertheless, the main body and the Supreme Headquarters broke through on 9 June. Tito was wounded, but the command structure survived. That is why German commander Rudolf Lüters judged the Partisans well organized, well led, and possessed of surprisingly high morale. At Neretva and Sutjeska they did not defeat the Axis in a straightforward contest of strength. They survived with an inferior force, difficult terrain, a hospital, and civilian refugees slowing every movement, without disintegrating. That survival helped persuade the Allies in 1943 to recognize Tito and increase support, and it supplied the military credibility behind AVNOJ’s claim at Jajce in November to speak for Yugoslavia as a whole. The federal project was not made only in a meeting hall. It rested on a command that had brought fighters and wounded people together through the encirclement and out the other side.

What kind of country would the armed movement build?

When Italy announced an armistice with the Allies on 8 September 1943 and signed the instrument of surrender on 29 September, the war in Yugoslavia entered a new phase. It was not simply that one occupying power disappeared. A political and military vacuum opened. Italian troops had been stationed in Dalmatia, Montenegro, parts of Slovenia, and the Adriatic islands. When they abandoned their weapons or were disarmed by German forces, the Partisans captured not only rifles and machine guns but also artillery, vehicles, and communications equipment. Some Italian soldiers and Yugoslav prisoners joined their ranks. The importance of the weapons was therefore not only numerical. Across wider areas of the coast and interior, the Partisans could organize administration and mobilization at the same time, turning armed villagers into mobile formations. Yet the gain did not provide a secure rear. German forces soon occupied much of the former Italian zone, while Ustasha and other collaborationist violence continued. The captured arsenal gave the movement time and capacity to build military and political institutions while facing a larger German offensive, not a guarantee of safety.

Under these conditions, the AVNOJ meeting at Jajce on 29 November 1943 translated an existing military reality into a claim to state power. The first session had created a nationwide anti-fascist representative body. The second constituted AVNOJ as Yugoslavia’s highest legislative and representative authority and created the National Committee for the Liberation of Yugoslavia to exercise executive power. This was the Communist leadership’s decision to establish a wartime provisional government. The government-in-exile and the monarchy could still be treated internationally as Yugoslavia’s legal representatives, but inside the country the liberation committees and the Partisans were the institutions actually collecting resources, recruiting, distributing food, and administering justice. AVNOJ sought to convert that practice into institutional legitimacy. Its decisions also barred King Peter II and the government-in-exile from returning until the war ended, while declaring that the people would then decide between monarchy and republic. Formally, the final choice was postponed. In practice, the route by which the prewar monarchy could simply resume its authority was closed.

The federal plan was not merely an administrative rearrangement. It proposed a state community of six equal republics, including Slovenia, Croatia, Serbia, Montenegro, Macedonia, and Bosnia and Herzegovina. The Communist calculation was shaped by the conditions of the war. Ustasha mass violence, the Chetnik vision of a Serb-centered monarchy, and Axis partition had turned national fear into a material force. Restoring the prewar centralized kingdom could therefore revive distrust among armed rivals and threatened communities. Federation offered each national group a place as a subject of liberation while retaining unified command over the army, foreign policy, and economic coordination. A critical assessment must also note that most delegates were selected within a movement controlled by the Communist Party and protected by its armed forces, so the settlement narrowed postwar political competition in advance. From the Partisan point of view, however, Jajce named what the struggle was for before victory had been secured. The movement was now both an army fighting occupation and a power exercising the rights of a new state in territory won by arms.

Turning a liberated capital into an army and a government

The liberation of Belgrade was not simply a military operation that recovered a capital. On 20 October 1944, the Partisan 1st Corps finished the fighting in the city alongside the Soviet 3rd Ukrainian Front commanded by Fyodor Tolbukhin. Soviet tanks and heavy weapons were decisive in cutting German routes of withdrawal, while Partisan infantry, familiar with the city and its approaches, seized streets and bridges. This cooperation did not make the Partisans proxies of a foreign army. Tito used Soviet operational support to enlarge his own military and political initiative. While consulting Moscow about the operation, he also sought to prevent the Red Army from becoming a long-term occupying power in Yugoslavia. Soviet forces did withdraw from Belgrade, and administration and security in the capital remained in the hands of the national liberation movement.

Yet a victorious army did not automatically possess national legitimacy. To exclude the monarchy in exile and the Chetniks of Draža Mihailović, supported by Britain, the power created by AVNOJ in occupied territory had to be translated into the language of domestic administration and international diplomacy. In November 1944 Tito and Ivan Šubašić, representing the royal government in exile, signed the Tito–Šubašić Agreement. Its surface was compromise. The question of the king was left unresolved for the moment, while a coalition government combining representatives of the national liberation movement and the government in exile was proposed. From the Partisan side, this was a tactic to secure Western Allied recognition and gain time until the postwar elections. From the royalist side, it was the last channel for preventing Communist one-party rule and preserving the monarchy’s legal continuity. But behind the formal balance permitted by the agreement, the Partisans already controlled the armed forces, police, and administrative networks of the liberated areas. The compromise did not divide power equally. It more closely translated existing Partisan power into the form of a state.

That translation was completed on 1 March 1945. The National Liberation Army and Partisan detachments were consolidated as the Yugoslav Army. The measure stripped the guerrilla formations of their local and explicitly political status and gave the state a regular army organized into corps, divisions, and military districts. The change of name declared that the war was entering its end, but it also answered who could legally possess weapons. Chetniks and collaborationist forces lost the space to survive as independent military-political actors. This consolidation was not a spontaneous national reconciliation. In northern Yugoslavia, retreating anti-Partisan forces and civilians were captured, executed, or interned, while postwar trials and purges combined punishment for occupation-era crimes with the removal of revolutionary competitors. The Yugoslav Army of 1945 was therefore both a product of liberation and a state apparatus created by the victor of a civil war. The Partisans changed from the force that had seized the capital into the army of the state, but that state rested on military victory, a federal promise, and coercive exclusion of its rivals.

What the victory decided, and what it left unsettled

The Partisan victory decided more than which army would enter Belgrade first. On 1 March 1945, the National Liberation Army became the Yugoslav Army, turning the wartime party organization and military command network into permanent state institutions. The federation of six republics announced at Jajce promised not simply to restore the prewar kingdom’s centralism, and the November 1945 election and founding of the Federal People’s Republic consolidated that promise into a constitutional order dominated by the Communist Party. The Partisans understood themselves not merely as the force that expelled Germany, but as a movement that would end the order of massacre and collaboration and build a state in which different peoples could live together. “Brotherhood and unity” compressed that claim. For people who had lived through Ustaša massacres of Serbs and the occupiers’ reprisals, it could appear a practical alternative to repeating a cycle of revenge among competing national states.

Liberation, however, was not the beginning of a neutral contest among parties. The return of the royal government-in-exile and Peter II was postponed, while the coalition space promised by the Tito-Šubašić agreement rapidly narrowed before the Partisans’ control of administration and armed force. The killings around Bleiburg in spring 1945, followed by forced marches and executions of defeated Chetnik and Ustaša-aligned soldiers and civilians, show that the new state did not separate liberation from revolution. The persistence of armed groups in the mountains into 1946 likewise shows that the end of occupation did not mean the end of political consent. From the Partisan standpoint, eliminating armed collaborators and preventing a renewed civil war were acts of state construction. To victims and opponents, they were victor’s revenge and the beginning of one-party rule.

Historians therefore disagree less about the fact of victory than about its meaning and cost. Yugoslav authorities put the wartime death toll at 1.7 million, while Bogoljub Kočović and Vladimir Žerjavić, working from demographic evidence in the 1980s, estimated roughly one million. The difference is tied to how scholars count Ustaša genocide, Chetnik attacks on civilians, occupier massacres, and Partisan executions during and after the war. One line of interpretation treats the Partisans as agents of multiethnic liberation and social revolution; another sees a communist revolution using the anti-fascist war to eliminate political rivals. Current scholarship need not erase either dimension. It can ask simultaneously how the Partisans really defeated occupation and rebuilt a state, and how that state, in the name of victory, restricted political pluralism and the lives of the defeated. The war settled the birth of a socialist federation. It did not settle whether its different communities would accept that federation as their own state.