This piece hardly qualifies as one of Trotsky’s major theoretical writings, but it has not appeared in English since it was first published in the Russian Press Review in 1920. We have been unable to find the relevant copy of that journal, so the version printed here has been translated from the 10 October 1920 issue of the French-language Comintern publication Bulletin Communiste.

COMRADE MILKICH has sent me a copy of your letter and the attached reports. En route to the Southern front, where the decisive battles against Wrangel must take place in the course of the next few weeks, I have been able to study your letter attentively. On rereading it, the atmosphere of the Yugoslav and particularly the Serb workers’ movement came back clearly to my memory.

The Balkan War was in effect the opening, the entrance to the great World War. It was then that socialists had to undergo the first test of their faithfulness to their flag. In the Serb party there were hesitations and disagreements, but they did not have time to develop and, as I recall, they ceased with the conclusion of peace. Kaclerovich has definitely gone over to social-patriotism. Lapchevich has maintained a strong and decided attitude – but I recognise with the greatest sadness that Lapchevich represents not the future but the past. It fell to us in the course of that cruel struggle to lose many friends. Some perished in the material sense, others in the spiritual.

Speaking of those who have really died, I remember above all the image of our friend Dmitri Tutsovich. His loss is felt, I am sure, up until today in the Yugoslav and Balkan movement. He was one of the strongest figures. Unshakeable, solid and full of assurance, Toutsovitch had been created for that epoch of humanity. What a misfortune that he should die before entering onto the new road of our revolutionary epoch.

Dushan Popovich is no longer among us either. I know that he was not at all exempt from social-patriotic errors. But I would like to believe that this determined fighter, this young and talented journalist, would have been with us, with all his powerful thought, in the camp of the revolution and Communism.

It was with gladness that I found among the leaders of the Communist movement in Yugoslavia the names of comrades whom I have known since 1912. I will not indicate their names in order not to harm them in the eyes of the Yugoslav authorities. I am less familiar with the movement in the former Slavonic provinces of the Habsburg empire. But to get an idea of it, it is enough to know that the socialist organisations of these regions reflect the general spirit of Austrian Social Democratic politics, that is, the cowardly spirit of submission to the will of governments, the spirit of legality at any price, the spirit of reformist illusions and chauvinistic prejudices.

From the words of comrade Rakovsky I know that the leaders of the Transylvanian socialist movement, in their union with the Romanian Socialist Party, brought to it the spirit of the lowest parliamentary opportunism. From your letter it is evident that the leaders of the workers’ movement in Croatia, Slovakia and Bosnia have turned to social-patriotism. You are conducting a decisive struggle against them and, as always in such a case, the masses are on your side. Your last Congress at Vukovar was the best proof of that. The Communist Party numbers around 60,000 members, an enormous force in Yugoslavia where the bourgeoisie of the different provinces seems pulled from all sides and weakened by internal divisions. The trade union organisations in Serbia found themselves after the war under the direction and influence of the Social Democratic Party. At present, as seems evident from your letter, the Communist organisations of Yugoslavia hold and increase their influence over trade unions which unite 150,000 proletarians. So far as it is possible to judge from here, your movement is following the true revolutionary road.

During the imperialist war, the demand for the "liberation" of Serbia from the claws of Austria-Hungary played a major role in the propaganda of Anglo-French imperialism – that is, in the duping of the working masses. Serbia has emerged from the war with an enlarged territory. It has expanded into the lands belonging to Austria-Hungary and Bulgaria and has become Yugoslavia. But little Serbia never found itself in an enslavement as great with regard to Austria-Hungary as big Yugoslavia does with regard to France and the Entente in general. Victorious Yugoslavia is no less ruined and exhausted than its defeated enemies. To this it must be added that if the destroyed economy of Europe is regenerated on the old foundations, the capitalist recovery of Yugoslavia, Bulgaria, Hungary and Austria will inevitably bring new bloody clashes between these countries. Only the socialist revolution in the Balkans and in Central Europe can create favourable conditions for the peaceful regeneration and economic recovery of the Yugoslav working masses. Only the Soviet Balkan Federation closely tied to the federations of Central Europe will allow the different nationalities established in these regions to unite their forces in peaceful collaboration instead of fragmenting and dividing them.

The proletarian revolution is on the move, and will not be held back. It demands the unanimous organisation, solid in combat, of the working class. Unite all your forces, comrades, in order to create such an organisation. In the name of the coming Proletarian Revolution I greet the fraternal Yugoslav Communist Party.

Kharkov, 10 October 1920