Ukraine's 'Reassurance' Force Needs to Go Big — or Go Home

Bloomberg

07-04-2025

The line between a deterrent and an invitation to attack can be a fine one. As France and the UK draw together a coalition of the willing to deploy a 'reassurance force' to Ukraine, they need to make sure they don't end up the wrong side of that divide.
This is a critical moment for Europe, and I've nothing but sympathy for the views of those, such as retired US Lieutenant General Ben Hodges, who see putting boots on the ground in Ukraine as urgent and essential if Europe is to defend itself from Russia in Ukraine, rather than against a Russia that's operating from Ukraine. The question is whether, without the US by their side, they can.
Hodges, a former commander of the US Army in Europe, thinks so. 'You do without, mitigate the risk or generate it yourself,' he told me. 'I cannot believe you don't have that ability in Europe, plus Canada, plus Norway and the others. The Russians can't defeat the Ukrainians, so Europe should stop being afraid of its own shadow.'
Start with the mission, not a number, says Hodges. Give a commander the resources and rules of engagement to succeed. If the mission is to guarantee a ceasefire along a 1,000-mile-plus line of separation, it will require much more than the 25,000 personnel currently being discussed. 'Whatever comes at you, you have to be able to put a Storm shadow (cruise missile) down the snout of it, whether that's on a Russian airfield or in Crimea,' he says.
A report published this week by the London-based International Institute for Strategic Studies tries to match the continent's limited capabilities and reserves to different hypothetical force sizes for Ukraine. The paper is admirably clinical, but you can't help but read between the lines that this project faces a dilemma: What Europe can manage wouldn't be effective, and if it's effective, Europe probably can't manage it.
Douglas Barrie, IISS senior fellow for military aerospace, puts it this way: With a small force (of, say, 10,000), the concern is that you may just be inviting Russia to test it. With a larger one (say 60,000 to 100,000), you should have more deterrent effect, but you probably can't sustain it long. 'Moscow just sits on its hands and waits you out,' Barrie said during a press briefing on the report.
Europe's coalition of the willing seems to be considering an in-between force of 25,000, but that too might not deter a Russian attack or be sustainable without substantial US help with ISR (intelligence, surveillance and reconnaissance), combat engineering and suppression of enemy air defenses.
The less fulsome the US guarantees, the further from the battlefield the force is likely to be deployed, raising the question of what purpose a European brigade or two would even serve when sitting in, say Lviv, a city in western Ukraine that's closer to Berlin than to the front lines of Ukraine's eastern Donbas region.
Jack Watling, senior researcher for land warfare at the UK's Royal United Services Institute, thinks Europe shouldn't try. Russia, he points out, has just freed up 70,000 combat troops from Kursk alone, a region of Russia that Ukrainian forces had, for a time, occupied. That's more than the entire British army can field, and just a fraction of the troop numbers Russia now has in Ukraine.
On top of that, the Russian arms industry is working overtime; there's no reason whatsoever to believe it would suddenly halt in the event of a ceasefire. Nor is it likely President Vladimir Putin would suddenly back off and make nice with Europe again. His goal remains to break the North Atlantic Treaty Organization's Article 5 collective defense commitment, just as it was at the start of the war. Europe has been instrumental in enabling Ukraine to resist for more than three years, at the cost of Putin's pride and hundreds of thousands of dead and wounded Russian soldiers, so the Kremlin sees itself at war.
If Ukraine has to rely on Europe (rather than a departing US) for its defense, Europeans will have to focus sharply on the area where they hold a potential advantage, and that's in air power. They need to build capacity to suppress Russian air defenses and take control of the skies over Ukraine. If it isn't going to be strong enough to deter Russia, any ground force sent should be there to train Kyiv's troops and protect the airfields.
Europe has a kind of quicksand power that can at times be highly effective — and frustrating to more nimble rivals such as Moscow and Washington. But when it comes to war, the European Union's tendency to prioritize consensus over aligning capabilities with goals is just dangerous.
I don't know the right response to this dilemma, whether Hodges or Watling is right. Europe has an essential self-interest in defending against Russian expansion in Ukraine, so it needs to be ready to take risks. But it also needs to be coldly calculating about what any land force is for and whether it's fit for that purpose. Protecting Ukraine's skies and suppressing Russia's ability to launch missiles and glide bombs at Ukraine may be the most effective contribution it can make.
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