European institutions conduct digital public life on social infrastructure they have little say over. This creates a problem for sovereignty, as these platforms are where citizens find out what the state is doing and politicians perform politics. This results in European political communications with its citizens depending on foreign actors who are regularly explicitly hostile to Europe.

The open social web offers an alternative, but not yet a sufficient one. Federated networks are good at helping people take back individual control. Authority is distributed, and communities govern themselves and if you don't like a particular platform you can freely leave for another one. In European political terms, this is subsidiarity. But subsidiarity does not produce sovereignty on its own. Moderation intelligence needs to be shared without being centrally imposed. Abuse crosses server boundaries, while funding for public goods does not. The result is autonomy without collective capacity: everyone can act, but nobody can reliably provide what the network as a whole needs.

The next step is solidarity. The open social web has autonomous actors, but lacks an institutional level where they can make collectively work and govern their shared commons. This is what Europe is good at: creating structures where actors cooperate without being absorbed into one authority. Europe does not need to govern the network, but it can provide the institutional space where shared obligations are negotiated, funded and maintained.

Leaving foreign platforms creates autonomy. Digital sovereignty also requires the collective capacity that lets autonomous communities stay together afterwards.