Ukraine’s Longest Day

The first 24 hours of Ukraine’s much anticipated counteroffensive may be the longest day for the Ukrainian Armed Forces. As German Field Marshal Erwin Rommel said to an aide before the expected Allied invasion of Normandy in 1944: “The first 24 hours of the invasion will be decisive. … For the Allies, as well as Germany, it will be the longest day”—a statement immortalized by the blockbuster Hollywood film about the Normandy landings, The Longest Day. Rommel knew that the initial phase of an attack often shapes the character of the subsequent fight, decides victory or defeat, and determines the strategic impact of an offensive.

Most of the speculation and debate is about when and where Ukrainian forces will strike, how big an attacking force Ukraine has assembled, and how much of an impact newly supplied Western weapons will have. It’s unlikely that anyone outside Ukraine’s high command knows whether Ukraine now has a decisive advantage in firepower, munitions, troop numbers, and battlefield logistics. What we do know is that in recent months, the war has increasingly been defined by attrition—neither side appears to have a decisive advantage, and each is trying to wear the other down. Whatever happens on Ukraine’s D-Day, it will not be easy for Ukrainian forces to avoid the war’s character as one of attrition, even if they are large, well-prepared, and well-equipped.

There is perhaps only one way for Ukraine to escape the scourge of attrition in the opening hours of the upcoming offensive: set off paralysis in the Russian military leadership and panic across the Russian rank and file. Ukraine’s greatest chance of success will come if Russian soldiers skedaddle from advancing Ukrainian forces without putting up much of a fight. Even if the correlation of forces were advantageous for Ukraine, that alone would not be sufficient to attain these effects. Rather, intangible factors such as tactical surprise, battlefield leadership, and fighting morale will likely be decisive in the first 24 hours of an attack. These intangible factors—not weapons alone—will help define whether the Ukrainians succeed in panicking the Russians, paralyzing the Russian military leadership, and causing a temporary breakdown of command and control. In this scenario, Ukrainian armored columns punch through layered Russian defenses, quickly advance into the Russian rear, and threaten command and control nodes like military headquarters and supply centers, compounding the panic and paralysis.

This kind of breakdown on the Russian side is exactly what took place during Ukraine’s lightning counteroffensive in September 2022 in Kharkiv oblast. The Ukrainians had set the conditions for the attack with a campaign of artillery attacks. Then, even though the Russians had observed the Ukrainian buildup, the attackers achieved tactical surprise, committed superior numbers, caused temporary panic, and set off a breakdown in Russian command and control. All of this delayed the speedy dispatch of Russian reserves that might have steadied the front line. As a result, Ukraine liberated more than 6,000 square kilometers of Russian-occupied territory in 10 days. The first 24 hours of that offensive were decisive, as the initial Ukrainian advance and exploitation of the breach in the front line triggered chaos and panic on the Russian side. In the upcoming spring offensive, Ukraine will likely attempt to replicate the Kharkiv offensive’s lightning character.

Achieving tactical surprise in the opening hours of the offensive will be crucial, since it increases the chance of local fire superiority and an advantageous correlation of forces, at least for a short period of time. This does not require Ukraine’s assembling of forces to remain secret—an unlikely proposition in any case, given satellite imagery as well as cheap and pervasive drones on the battlefield. Rather, to stretch out Russian forces and prevent a concentration of defenders, Ukraine will need to leave Russia in the dark about where and when those assembled forces will strike. At the same time, Ukraine will need to make sure that the location chosen for the breakthrough attempt can be quickly expanded to enable deep penetration—for example, by swiftly seizing important roads, intersections, or railroad junctions.

Of course, Russian defenses will need to be overcome first. A Ukrainian intelligence analyst shared a detailed description of echeloned Russian defenses in the south of the country: a formidable network of minefields, pyramid-shaped concrete blocks known as dragon’s teeth, anti-tank ditches, dugouts, and trenches. What’s more, since the defeat in Kharkiv and retreat from Kherson, Russia has now deployed a greater number of troops along a significantly shorter front line.

It will be very difficult for Ukraine to achieve sufficient fire superiority to quickly destroy these layered defenses, and it will be similarly hard to concentrate enough troops to quickly seize Russian positions. (A successful offensive usually requires the attacker to substantially outnumber the defender.) Gaining momentum under heavy Russian fire will be especially difficult given the need to overcome the layered defenses: Clearing a lane of land mines for tanks and other vehicles to traverse, clearing the dragon’s teeth, and breaching the ditches all require specialized equipment and skills. The more likely avenue to success is for the Ukrainians to force the Russians to abandon their defensive positions without much of a fight—perhaps by triggering a panic that their positions got flanked and are now in danger of being cut off and encircled. That might be accomplished by finding a spot in Russian defenses where the layers are weaker, significantly attriting Russian forces with localized and temporary fire superiority, and advancing into the defenders’ rear. This may be the only realistic option for Ukrainians to achieve a quick and deep strategic breakthrough.

In this initial phase, tactical leadership will be crucial, especially the ability to make and execute decisions at lower command levels to exploit various opportunities on the battlefield. Every military operation is, in one way or another, organized chaos. This is even truer for attackers: Units may take the wrong turn, coordination may be difficult because of enemy jamming of communications, and even precisely determining the enemy’s whereabouts is a lot harder while on the move. Solid tactical leadership is crucial for overcoming, or at least mitigating, the friction inherent to war.

Leadership on the battlefield is also crucial because it has a direct impact on fighting morale. Soldiers who don’t trust their military leaders because the latter seem overwhelmed by the friction of warfighting will quickly see their morale evaporate. If that happens, it is among the Ukrainians that panic could break out in the opening phase of the offensive. Junior tactical leaders will have to spot weaknesses in the Russian defenses and quickly exploit these by pushing as many armored formations as possible through that particular spot to get into the Russian rear. This requires taking huge risks—for example, by temporarily operating outside the air defense umbrella—and consequently demands highly motivated troops. Whoever has the upper hand in tactical leadership and morale at the onset of the attack will be less likely to panic and more likely to have a tactical advantage likely lasting beyond the first 24 hours.

Beyond tactical surprise, leadership, and morale, there is another factor that will determine the success of the counteroffensive: To what degree will the Russian side be able to quickly mobilize its operational reserve? This, too, will largely be determined in the first 24 hours. If a general panic clogs roads with retreating Russian forces, mobile reserves held in the rear will have a tough time reaching the front line at the point of breakthrough—if these Russian reserves are available at all.

The first 24 hours of the upcoming spring offensive may indeed be the longest day for Ukraine. In the long run, Ukraine’s armed forces will have a tough time escaping the crucible of attrition of this artillery-focused land war. The Ukrainians could achieve tactical success if they are able to cause paralysis in the Russian military leadership and panic among troops, triggering a rout in the opening phase of the counteroffensive. Whether this will be sufficient for Ukraine to achieve long-term strategic gains—let alone win the war—is another question entirely.