The moral disadvantages of foreign volunteers are less obvious. Before the war, some predicted that Ukraine would not fight at all, and would acquiesce to its invasion and absorption into Russia. If Ukraine had not resisted, one might have wondered whether Vladimir Putin had a point, and Ukraine was a fake country whose absorption was natural. This hypothesis could be falsified only by a national resistance—which Ukraine has amply provided. The country has fought back, under Ukrainian leadership, and appears willing to keep doing so. Plenty of countries have relied on foreign fighters to ease them into existence. But the sure sign of a country’s objective reality is that it insists on being born with or without the aid of foreign midwives. Putin will say (and is already saying) that Ukraine survived the invasion only because outsiders intervened. Better that the Ukrainian victory be as Ukrainian as possible.

Kacper Rękawek, who studies foreign fighters at the University of Oslo’s Center for Research on Extremism, told me we should expect that when Russia captures foreign volunteers, it will put them “on Russian state TV, 24/7, to say, ‘Look—NATO has arrived.’ It will be too good to be true.” The experience of Aiden Aslin, a volunteer from Nottinghamshire, England, confirmed that prediction. After Russia captured him in Mariupol, he was paraded for interviews, including this one with a Putinophilic fellow Brit.

So the foreign volunteer lacks local knowledge, and his presence undercuts foundational moral claims.