Having spent a significant chunk of 2021 in Ukraine, I followed the Russian invasion closely. When an opportunity to return to the embattled nation popped up earlier this spring, I jumped at the chance and was anxious to see for myself what was really happening.

Having been here a little more than a month this time around, I don’t claim to have the definitive take on the situation, but I’ll go ahead and make my not-as-bold-as-it-would-have-been-in-March prediction: The Ukrainians will eventually push the Russians back to their borders, retaking Donbas; Crimea is literally a bridge too far, though, and will remain under Russian control unless the international community takes steps to force them out.

A popular joke here is that in January Russia had (or at least was perceived to have) the second-most powerful army in the world; now it has the second-most powerful army in Ukraine. No one outside Ukraine gave the Ukrainian military much chance of making an effective stand against the Russians, but anyone who has paid attention has been inspired by their will to fight and resourcefulness. Will is a difficult variable to measure until armies are actually in combat, which is why Ukraine’s combat power was underestimated and Russia’s was so badly overestimated.

As I’ve watched and interacted with Ukrainian military counterparts, I’ve been impressed by their humility, adaptability, and innovation. The Ukrainians acknowledged their poor performance after the initial Russian invasion in 2014 and have essentially rebuilt their entire military since. They welcomed Western trainers (primarily from the U.S., Canada, the United Kingdom, and Baltic States), soaked up the tactics, techniques, and procedures, then adapted them to suit their culture and understanding of their enemy. Even now, while still in the midst of a difficult fight, their demand for training exceeds the limited capacity of my organization (which receives no support or funding from any government, including the U.S.) to provide it by a factor of 10 or more.

After years spent working with Global War on Terror (GWOT) partners who were often disinterested and had a limited sense of what Americans would think of as patriotism — nation before self — it’s been refreshing to work with Ukrainians who have put personal interests aside and ask insightful questions and think outside the box as they go through similar training. The Ukrainians don’t see Russian troops as misguided brothers (as Afghan President Karzai once described the Taliban), but as bloodthirsty, amoral demons, and their determination to improve their tactical performance and push the Russians out of their country reflects it.

My favorite anecdotes demonstrating the Ukrainians’ ability to adapt and innovate involve their use of drones. They’ve made great use of the Turkish Bayraktar drones they purchased, to include taking out 1) an air defense system, 2) a landing craft loaded with a replacement air defense system, and 3) a helicopter landing special operations troops, all on the infamous Snake Island, which itself has become a powerful symbol of Ukraine’s refusal to the bow to Russian aggression.

They’ve also adapted commercial drones — identical to ones you or I could buy online — for military use. One video — filmed by the drone’s camera — shows a grenade modified with Ukrainian-developed 3D-printed tail fins being dropped through the sunroof of a car being used by RF soldiers (NSFW). There’s no shortage of memes noting the Ukrainians’ return on investment from using drones that cost a few thousand dollars to destroy armored vehicles that cost the Russians hundreds of thousands.

After a slow start, the U.S. and other Western governments have delivered a steady stream of lethal aid that has been a key element in Ukrainian success. Despite attrition (which is hard to gauge thanks to the Ukrainians’ lock-down operational security measures), the Ukrainians’ capacity (quantity) and capability (quality) continues to improve, while the Russians’ pre-war numerical advantage is dwindling rapidly. And sanctions will limit the Russians’ ability to replace what’s been lost. Observers noted Russia’s movement to the front earlier this week of T-62 tanks that entered service with the Soviet Army over 50 years ago, while the Ukrainians recorded the first-ever kills (of much newer Russian tanks) with U.S.-provided Switchblade “kamikaze drones.”

The Ukrainians have performed well and continue to exceed expectations. They’ve eliminated the threat of Russian ground forces in and around the capital of Kyiv; they’ve pushed the Russians back — out of artillery range and almost back across the Russian border — from the second-largest city of Kharkiv; and they’ve mostly held the line in Donbas, where most of the fighting is currently taking place. They’ve got a lot to be proud of, but it’s come at a very high human and financial cost.

There is still much work to be done to restore the territorial integrity of their country. If current performance is an accurate predictor of future results, I believe the real question isn’t whether the Ukrainians will eventually prevail but what it will cost to achieve that victory.