The irony is that had the Chetniks won (here insert the usual unlikely POD's about a timely Anglo-American landing on the Adriatic etc.) they would have had as plausible grounds for accusing Tito of collaboration with the Germans as he had of accusing them! See Geoffrey Swain,
Tito: A Biography, pp. 58-60:
***
"This assault on the Cetniks was made possible by one of the most controversial episodes of the partisan war, the approach made to the Germans in March 1943. On several occasions during the partisan war there had been talks with the Germans to facilitate prisoner exchanges...During the fighting on the Neretva in early March, Tito decided to initiate discussions with the Germans once again. This time his aim was more than just an exchange of prisoners, he wanted to gain a respite from the German assault so that the partisans could finish off the Cetniks in Hercegovina and Montenegro; should an Allied second front ever involve a British landing on the southern Adriatic coast, he wanted to be sure they were welcomed by partisan rather than Cetnik forces. With Montenegro secure, the partisans could again turn their attention to Serbia.
"During the recent fighting a high-ranking German officer had been captured, Major Stoecker. Djilas recalled how 'Tito brought together the Central Committee members — Rankovic, Pijade, and me — in his water mill by the Rama River, and suggested that we send a letter to the Germans through Major Stoecker proposing, in addition to an exchange of prisoners, that the wounded and prisoners be treated according to international conventions, and demanding specifically that the Germans recognise us as a belligerent force'. The Germans replied positively a few days later and on 9 March Tito, Rankovic and Djilas agreed that Djilas should be sent to conduct the negotiations, accompanied by Vladimir Velebit who had studied German in Vienna and was a lawyer. Djilas recalled that he asked Tito what he thought the Russians would say, and Tito replied almost angrily 'well, they also think first of their own people and their own army'. Djilas's brief was to move beyond discussion of prisoners, the wounded and belligerency and to persuade the Germans that the partisans' chief objective was not to penetrate into Serbia, but simply to win control of the Sandjak from the Cetniks. The Germans needed to believe the Sandjak was the anticipated future partisan territory and the cetniks their main enemy; the Italians would be fought only in as much as they supported the cetniks, and, since the partisans had no designs on Serbia, fighting with the Germans was unnecessary. Djilas insisted that during his talks there was not a word said about the cessation of fighting between the Germans and the partisans, but 'this too was understood', and for six weeks there was 'a de facto ceasefire.'
"The prisoner exchange was quickly negotiated in Sarajevo, before Djilas and Velebit pressed on to Zagreb where the serious talks began on 26 March. In the two meetings held, the Germans indicated that they would cease operations against the partisans as soon as the partisans stopped carrying out raids on the strategic railway line passing through Slavonia. Tito responded by instructing the Slavonian partisans to suspend operations, and, to encourage agreement, Djilas told the German negotiators that the partisans 'would fight the British if they landed'. Djilas then returned to partisan headquarters, while Velebit continued the discussions in Zagreb. Rankovic had always been more dubious about the outcome than Tito, and his doubts proved justified. Before the negotiations began, the German ambassador in Zagreb had sent a telegram to Berlin on 17 March in which he reported the possibility 'that Tito and supporters will cease to fight against Germany, Italy and Croatia, and retire to the Sandjak in order to settle matters with Mihailovic's cetniks.' The ambassador felt that 'the possibility exists that Tito will demonstratively turn his back on Moscow and London, which left him in the lurch.' The ambassador made clear that in his opinion 'this possibility should be pursued'. Receiving no reply, he wrote again on 26 March, explaining that the talks with Tito's representatives had begun, and there was a real possibility of 'saving manpower and blood'. However, on 29 March Ribbentrop, after talks with Hitler, informed his ambassador that all contacts with the partisans should be broken.
"It was only on 30 March that Tito informed the Comintern that a prisoner exchange was being negotiated with the Germans, and when he did so he sought to hide what was really going on by playing on Soviet concerns about their British ally. Tito stressed that the partisan delegation had gleaned useful information from their conversations in Zagreb. Leading officials in Germany, he reported, doubted there would ever be a British landing in Europe, since the British outnumbered the Germans five to one in Africa and still undertook no serious operations. The partisan delegation had also learned that the Germans suspected the Italians of being in secret contact with the British. Tito added: 'Not only among our fighters, but also among the peoples of Yugoslavia as a whole, hate towards the English is growing because they are not opening a second front in Europe, that they want in this way to weaken the Soviet Union in its struggle against Germany — please advise on how to act in this mantter'. Lost in the middle of the report was the statement that the Germans recognised the partisans as their serious enemy and were ready to hold talks with Tito. Dimitrov was not fooled and asked at once 'what is going on here?' Any contact with the Germans was harmful, he stressed. Tito mentioned only the prisoner exchange when he replied on 31 March, and again tried to throw up a smoke screen. His reply stressed not the exchange of Major Stoecker but the hundred Croat prisoners who, if not exchanged, would otherwise have to be fed, which was impossible, or shot, which was undesirable. He reassured Dimitrov he had no intention of going to Zagreb himself, he just thought it ironic, given what the occupation press had been writing about him, the Germans were nevertheless prepared to talk. In another attempt to pull the wool over Dimitrov's eyes, Tito added that Djilas's delegation to Zagreb had also been instructed to obtain badly needed medical supplies to combat typhus.
"The Zagreb talks gave the partisans some much needed respite; that was their purpose and to that extent they succeeded. Much later their discovery would inflame historical debates about who collaborated in Yugoslavia and who resisted. Allegations of collaboration against the Cetniks rest on the charge that they were trying to get the Germans and Italians to act together with them in a war on the partisan's. Tito's collaboration, if such it was, was rather different. His ultimate aim was to trick the Germans, by bravado about an Allied landing, into allowing him a free hand against the Cetniks; but lesser outcomes, like recognition as a combatant force, would be a bonus, and simply stalling for time would be useful. Time was of the essence for the partisans now anticipated a long struggle..."
https://books.google.com/books?id=BFgBAwAAQBAJ&pg=PA58
