Like a modern-day Ernie Pyle or Timothy O’Brien, Matt Gallagher heads to Ukraine — not to embed with the Ukrainian soldiers fighting against Russian aggression, but with the many others who have converged to help however they can. Are there Halliburton types here? Of course. But by and large, this is a portrait of men and women who are fighting based on what’s right and wrong, not what’s profitable.

In the language of this new war, McNulty is a “volunteer,” one of roughly tens of thousands of internationals and local Ukrainians who’ve devoted themselves to supporting the resistance against the Russian military. The roles they play vary widely, from humanitarians like McNulty to social-media celebrities fundraising for military units. There are brash foreign fighters and humble food drivers and furtive gunrunners and ancient babushkas knitting camouflage ghillie suits in community gyms. Some are volunteers in the literal sense, burning through their savings to subsidize their work. Some earn a small stipend; still others are profiteers who see nothing wrong with benefiting financially amid a nation’s war for survival. It’s proven dangerous work, too—in January, two British volunteers were killed attempting to evacuate an elderly civilian. In February, American Pete Reed, another Marine veteran, was killed when an antitank missile hit his ambulance. For all the differences in type and approach, the volunteer movement is unified by a core belief that this is a fight worth fighting, that Ukraine is worth defending.