When French prime minister Élisabeth Borne stood up in parliament to push through her controversial pension reform, MPs from the left-wing France Insoumise reacted in a way that their counterparts in many European countries wouldn’t — that is, by singing the national anthem. Unlike Britain’s dismal “God Save the King,” France’s thundering “La Marseillaise” is at least a song rooted in revolution — or more precisely, in revolutionary war. But its strident patriotism means it surely isn’t beloved by all left-wingers, even in France.

The Left’s relationship with patriotism and national identity has no single “solution” — not least given that it doesn’t mean the same things in all countries. Socialists in liberal democracies in the imperial core can hardly address the problem in the same way as parties leading the armed resistance to colonial occupation. Yet, the “national question” has surely inspired a great deal of reflection on the Left, producing different schools of thought that provide insight into the problem today.

Jean-Numa Ducange is a historian of the socialist movement, with a particular focus on France and German-speaking countries. His recent book, Quand la Gauche pensait la Nation (When the Left Reflected on the Nation), discusses how socialists at the turn of the twentieth century thought about the “national” dimension of their politics and how it fit together with their proclaimed internationalism.