Over the past few weeks, the Ukrainian Armed Forces have been making use of very precise, long range rocket systems against the Russian invaders. HIMARS, short for High Mobility Artillery Rocket System, is an American truck mounted rocket launch platform. It is a lighter, more deployable version of an older tracked launcher that was employed to great effect during the Gulf Wars.

The HIMARS, because of its range and accuracy, is a weapon for attacking targets deep behind the front line of fighting. It can be used to destroy critical communications nodes, command posts, airfields, and important logistics facilities. These are the targets that have been the focus for Ukraine in the past few weeks.

Because it is a mobile system, HIMARS is also able to halt, shoot and then move away quickly. This ensures that it is a highly survivable weapon system in an era where the time between detection and destruction can be just a few minutes. This helps keep it safe from the Russian preponderance in artillery in Ukraine.

Perhaps the most important impact of HIMARS is that it has allowed the Ukrainians to return to their preferred way of war. Back in May, I described the Ukrainian strategy — up to that point — as a strategy of corrosion. This strategy of corrosion has seen Ukraine attacking the Russians where they are weak, while also using some of their combat power to delay Russian combat forces.

In this war’s initial battles, the Ukrainians attacked the weakest physical support systems of the Russian army in the field — supply routes, logistic supply hubs, artillery and senior commanders in their headquarters. The Ukrainians corroded the Russian forces — and eventually their morale — from within and forced their humiliating retreat before Kyiv and Kharkiv.

But in the east, the Russians changed tactics. They concentrated their forces on a single large offensive, used their advantage in firepower and forced the Ukrainians into an attritional battle for the Donbas. This relentless, crunching attrition is Russia’s preferred way of fighting; it is an inherent part of their military culture. And it is a way of war that the Ukrainians cannot afford to wage.

The introduction of HIMARS has once again changed the battlefield calculus in the fight for Ukraine. Over a dozen major Russian supply depots, used to store artillery ammunition, have been destroyed by HIMARS rockets in the past week. The Ukrainians have also attacked Russian command posts, killing even more senior Russian commanders. And they have used it to destroy Russian air defence systems, allowing the Ukrainian air force greater freedom to support the fight on the ground.

The Russians are having to quickly adapt, and disperse their already tenuous logistic system, making them even less efficient. And the Ukrainians, now able to move away from the attritional fight they were drawn into in the east, are re-adopting the asymmetric conventional tactics for the east that they used so successfully around Kyiv and Kharkiv.

As well as the physical impacts, there is a psychological effect on the Russians. More of the invading Russian force is vulnerable to an attack from HIMARS. Russian soldiers have seen its impact firsthand, and on social media. The new long-range rockets are having psychological impacts on the Russians, which will have an effect on a force already suffering from poor morale.

Despite this, HIMARS is not a wonder weapon. It is having an important impact and will continue to do so, but HIMARS alone will not win this war. Military forces are complex organisations with many different capabilities in function, range, time and impact, all orchestrated by clever humans. HIMARS is one part of this complicated tableau.

The Ukrainian strategy of corrosion, newly supported by HIMARS, is how clever twenty-first century military organisations must fight if they seek to win. The Ukrainians have proved to be masters of corrosion in this war. They offer valuable lessons to the West’s military institutions for their own inevitable future struggles against authoritarian regimes.