Fighting a war is really difficult – as we constantly find out every time a new one is started. Though they may begin with hopes of lightning invasions and victory parades, they often end in protracted, bloody catastrophes. This is the situation facing Russia’s leaders today. 

They started this war with a wholly unrealistic understanding of what they were doing. They both drastically overestimated the capacities of their own armed forces and ludicrously underestimated those of Ukraine. The upshot is that their initial strategy is in tatters, and the Russian army is in a poor position, struggling to make gains, and actively in retreat in several areas.

The question that now faces them is whether they are able to adjust their strategy. As part of this adjustment, we are now faced with the prospect of shifting to a much lengthier conflict that will see Russia mobilise its supposedly superior resources. This “long war” idea fits in well with one of the most common and enduring visions of Russian military power: the idea that Russia conquers through the use of mass and overwhelming force. That might give comfort to extreme Russian nationalists – but it must be understood that the Russia of today is very different militarily and economically from the “mass strength” Russia of the past.

The Russian military has been significantly reduced over recent decades, and its entire armed forces are made up of 900,000 or so personnel. A large number of this force remain conscripts, whom the Russian state needs to be very careful about using in Ukraine for both political and military reasons. The Russian military has already deployed approximately 75 per cent of its most effective land-fighting forces, its Battalion Tactical Groups (BTGs). This force, the crème de la crème of the Russian army, is the backbone of that which has already experienced widespread setbacks, confusion and losses. 

It is increasingly clear that this initial force will be unable to conquer Ukraine. Indeed, there are signs that the Russians have already conceded that it is completely insufficient to achieve even the original first goal of the invasion, seizing Kyiv. Assuming that remains the aim, even if Russia throws in the remaining 25 per cent of its BTGs, it’s in no way clear that they could take the city. By the time they have deployed that force for attack, what remains of the original Russian army around Kyiv will be even further exhausted. And it should be noted that such a decision would basically leave Russia undefended by anything but nuclear weapons along its long and volatile border.

So, if Russia realises the blitzkrieg has failed and decides to embark on a long war, what happens? Here, it gets tricky. Russia can try and raise a new large, heavy army – but it will take time. It would have to use young, untrained conscripts and out-of-shape reservists in the first instance. It would take months, maybe even years, before such a force would be combat capable. The new army would have to be trained. It would have to be provided with new, up-to-date weapons (and the Russian wastage in Ukraine so far looks horrible), as well as new logistical infrastructure. And at that point this new, combat-inexperienced army would have to be committed against Ukrainian defenders who have been fighting in their country, have experience and know what they are doing. The evidence of atrocities, such as those at Bucha, which have been revealed by the Russian retreat, will only harden both Ukrainian resolve and that of the West.

Russia will have to do all this raising, retraining and re-equipping while living under some of the harshest economic sanctions in modern history. The Russian economy, already weak, will thus be taking on one of the most strenuous tasks possible at a time of maximum vulnerability.

So, can Russia fight a long war? Possibly. But the results are still not clear and the costs would be significant. It would tax Russian society and the Russian economy to the max, require the use of conscripts and leave the rest of Russia defenceless except for nuclear weapons. The blithe assumption that Russian victory is only a matter of time must be resisted. With the right support, Ukraine may yet force peace on its terms.

Phillips O’Brien is professor of strategic studies at the University of St Andrews