SOVIET–POLISH WAR. The Soviet–Polish War was just one—albeit the most prolonged, geographically extensive, studied, and perhaps internationally significant—of a series of conflicts that erupted in Eastern Europe as German forces withdrew from the region in the aftermath of the First World War. The retreat of Ober Ost and the collapse of the territorial settlement brokered through the Treaty of Brest-Litovsk (3 March 1918) left a power vacuum that was contested by local nationalist forces and Soviet Russia, although the nationalists also often fought among themselves, such as in the Ukrainian–Polish War and the Polish–Lithuanian War. (Other related conflicts were the Soviet–Ukrainian War, the Estonian War of Independence, the Latvian War of Independence, the Lithuanian Wars of Independence, and the Kinship Wars.) Polish aims, broadly speaking, as articulated by the preeminent Polish leader of the era, Józef Piłsudski, were to recapture territories lost during the partitions of Poland in the late 18th century and to create a Polish-led federation, the Międzymorze (or Intermarum, “the land between the seas”) of several East-Central European states, stretching from the Baltic Sea to the Black Sea, as a bulwark against the reemergence of both German and Russian imperialisms. (The two aims, it is worth noting, were to some extent conflicting, because if Poland recovered the lands lost in all three partitions, it would be in possession of territories claimed by its desired allies in Ukraine, Belarussia, and Lithuania.) Soviet aims were to repulse any Polish advance (which they regarded as a branch of the Allied intervention in Russia) and, potentially, to carry the revolution west through Poland to Central Europe.
Skirmishes began soon after the armistice of 11 November 1918 (although a case could be made for citing the Dowbor-Muśnicki uprising of January–February 1918 as the beginning of the conflict), but escalated rapidly following the Red Army’s capture of Minsk on 5 January 1919, as Belarussian, Lithuanian, and Polish self-defense forces began to organize for the defense of “their” homelands in what was an ethnically mixed region of intractable complexity. Hostilities remained at a relatively low level for most of 1919, however, as the Soviet government prioritized its campaigns against the Whites and Warsaw calculated that it was to its advantage to grant the Red Army a free hand to crush forces that were unabashedly committed to the reestablishment of a “Russia, One and Indivisible.” Moreover, this breathing spce merely granted the newly created Second Polish Republic the opportunity to begin concentrating forces along its still undemarcated eastern border; by September 1919, the Polish Army numbered 540,000 men, of whom 230,000 were deployed in the east. As the Whites fell back in the autumn of 1919, these forces began to engage with Red forces with increasing frequency, contesting the claims to sovereignty over the disputed border regions voiced by the newly created Litbel (the Lithuanian–Belorussian Soviet Republic, proclaimed on 27 February 1919), for example.
For its part, the Soviet government was seeking to preempt the imposition of a border such as that suggested by the Allies at Paris (the Curzon line), which it regarded as too generous to Poland. However, with the Red Army forced to concentrate its resources on the Eastern Front and the advance of the Russian Army of Admiral A. V. Kolchak, the Poles gradually gained the initiative during the spring of 1919. Forces under General Stanisław Szeptycki captured Słonim (2 March 1919) and crossed the River Neman; forces under General Antonu Listowski took Pinsk (5 March 1919) and crossed the Jasiolda (Iasel′da) River and the Oginski Canal; and other units entered the outskirts of Lida. (Although Poland also, it should be recalled, was distracted by its border disputes with Czechoslovakia over Cieszyn Silesia, Orava Territory, and Spiš and by the risings of Poles in Silesia against German rule.) The situation was then further complicated, during the summer of 1919, by the northward advance of the White Armed Forces of South Russia (AFSR), whose leadership appeared disinclined to recognize Polish independence, never mind negotiate about borders (despite the fact that the AFSR’s main commander, General A. I. Denikin, was half Polish). In the light of this, Piłsudski determined in April 1919 that, although his army should counter any Red incursions into territory held by Poland, it should avoid challenging the Red Army to a degree that might grant respite or succor to the Russian Whites. Nevertheless, the Poles not only pushed Soviet forces out of the recently captured centers of Grodno and Vil′na (19 April 1919), but launched a counteroffensive that led to the capture of Mołodeczno (4 July 1919), the Polesie region (10 July 1919), Minsk (8 August 1919), and Dubno (9 August 1919). Further advances were made in the northwest, with territory from the Dvina to near Daugavpils secured by early October 1919. Thus, by early January 1920, Polish forces had reached the line of Uszyca–Płoskirów–Starokonstantynów–Szepietówka–Zwiahel–Olewsk–Uborć–Bobrujsk–Berezyna–Dyneburg (Daugavpils).
In this period, Polish relations with the Lithuanian government were reaching crisis point over border issues (particularly their rival claims to Vilnius/Wilno), but Warsaw’s negotiations with the Latvian government at this time had some success, and by early 1920, Polish and Latvian forces were conducting joint operations against the Red Army (notably in the capture of Dyneburg/Daugavpils, 3–21 January 1920). In spring 1920, the Polish–Ukrainian War also drew to a close with the Treaty of Warsaw (21–24 April 1920), and thereafter Poland enjoyed a military alliance with the Ukrainian Army of the Ukrainian National Republic. This emboldened the Poles, as did the defeat of Denikin and Kolchak’s forces over the winter of 1919–1920, which had neutralized any threat of the establishment of a White government in Russia. Likewise, with the last significant White force (General P. N. Wrangel’s Russian Army) confined to Crimea, a peace settlement having been negotiated with Estonia (the Treaty of Tartu, 2 February 1920), and a cease-fire in operation on the front with Latvia, the Bolsheviks felt that their hands were now free to deal with Poland and potentially, to export the revolution to Europe.
What had essentially been, throughout 1919, a low-level border conflict, was thus primed to erupt into full-scale war. By April 1920, the Red Army had over 700,000 troops concentrated on its Western Front and South-West Front facing Poland; the Poles could draw on an army of approximately the same number. Anticipating a Soviet offensive, Piłsudski launched his own (“Operation Kiev”) on 24 April 1920. This was a joint operation, with the Polish 3rd Army (under General Edward Rydz-Śmigły), 6th Army (under General Wacław Iwaszkiewicz), and 2nd Army (under General Listowski) advancing into Ukraine alongside the two remaining divisions (around 15,000–30,000 men) of S. V. Petliura’s Ukrainian Army. It was initially a remarkable success; Kiev was captured on 7 May 1920. Preparations were then made for an offensive against Żłobin, to secure the most direct rail route between Kiev and Minsk (then in Polish hands). However, the Polish and Ukrainian attackers had failed in their objective to entrap defending Soviet forces, and the 12th Red Army and 14th Red Army had both retreated beyond the Dnepr in good order. On 15 May 1920, a Red counteroffensive was duly launched on the South-West Front (commanded by A. I. Egorov), with S. M. Budennyi’s 1st Cavalry Army joining the fray. Bolstered by over 100,000 new volunteers (responding to a flood of Soviet agitprop directed toward rousing anti-Polish feeling) and some 14,000 new officer volunteers (answering a call by the former tsarist commander General A. N. Brusilov urging fellow officers to join the Red Army), by 10 June 1920 the Red Army had Polish forces in retreat along the entire front and on 13 June 1920 recaptured Kiev. Over the following weeks, the Poles attempted a series of counterattacks (at Usza on 19 June, at Horyń on 1 July, and at Równe on 8 July), but Egorov and Budennyi’s men pressed on.