The reasons for this were partly political. It was clear to everyone that unless the Russian army advanced at the beginning of the war there was no chance of keeping Prussia as an ally. Right down to the winter of 1811–12 this issue hung in the balance, with a Russo-Prussian convention pledging Russia to an offensive signed but ultimately never ratified by the Prussian side. Another vital political issue was the competition to secure Polish loyalty. As Bennigsen argued in February 1811, a Russian offensive into the Duchy of Warsaw would stymie Napoleon’s wish to mobilize Polish support in Russia’s western borderlands. If the moral effect of a Russian offensive was combined with attractive political concessions to the Poles, large sections of the Polish army might fight on the Russian side.47
There were also powerful military reasons for an offensive. Invading the Duchy of Warsaw meant that Polish rather than Russian soil would bear the costs of war. More important, if Napoleon was to invade Russia, the Duchy of Warsaw and East Prussia would be his key bases. Huge stores would need to be amassed well in advance to sustain the invading army. As this army made its way across Europe to take up position on the Russian border their stores and their sources of food and fodder in the Duchy would be vulnerable to a Russian preemptive strike. For a sensible invader, the campaigning season in Russia was short. It was lunacy to invade before early June, when there would be sufficient grass in the field to feed the horses. That allowed less than five months before the snows began to fall in November. At the very least, a Russian pre-emptive strike might delay Napoleon’s plans for an offensive and gain an additional year for Russian defensive preparations.
Above all, Russian generals advocated an offensive because they understood how very risky and difficult a purely defensive strategy would be. The western border was immensely long. If Russia was still at war with the Turks, French or Austrian troops could invade Bessarabia and threaten the entire Russian position on the north shore of the Black Sea, at the same time as Napoleon’s main army was tying most of the Russian forces down in Belorussia and Lithuania. In the spring of 1812 peace with the Ottomans and the Austrian promise not to invade Russia from Galicia at least ended these worries.
Nevertheless the border with East Prussia and the Duchy of Warsaw alone remained very long. The Russians had to defend the approaches to Petersburg and Moscow. The latter could be threatened directly via Smolensk in the west or from Kaluga and the south-west. The defence of Kiev and Ukraine was also a top priority. Russian armies would therefore be stretched very thin. Communications through the huge area of the Pripet marshes were extremely poor. The Russian southern army defending Ukraine would be on its own. It would be within Napoleon’s power to block the two main roads across the marshes and turn most of his army against one or other half of the Russian defensive screen.
It was in the nature of a defensive strategy that it gave the enemy the initiative. Added to the geography of the western borderlands, it would give Napoleon every opportunity to drive through the Russian forces, keep them separated and defeat them in detail. Moving through the centre of the Russian armies, he would then have the advantage of being between them and using interior lines. Bagration, Petr Mikhailovich Volkonsky and the emperor’s uncle, Duke Alexander of Württemberg, all stressed this danger in the early months of 1812.48 To make the situation worse, in the impoverished western borderlands it was very difficult to keep large armies concentrated and static for weeks on end, except possibly in the weeks immediately after the harvest. Sickness rates also shot up once the army was concentrated. In addition, much the most effective way to eat up the region’s food supplies and deny them to the French was to quarter the Russian army across a large swath of the area and use it to requisition supplies in lieu of tax. A state of war was declared in the border provinces in late April, which helped with requisitioning, but army headquarters was loath to concentrate its forces too early and too narrowly. In any case, once Napoleon left Paris the sources of Russian intelligence partly dried up. Napoleon himself was hoping for a Russian offensive and did not make final plans for an invasion until very late. He then of course did his utmost to hide where he intended to make his main thrust. Not until late May 1812 did the Russians begin to get a clear sense of where the main enemy attack was likely to come.49
