BRUSSELS — Police officers in black RoboCop uniforms and Darth Vader helmets blocked ordinary citizens from voting. They beat people with batons, fired rubber bullets and wounded pensioners. All of it was captured by smartphones and news cameras and spread around the world.

It is the kind of violence the European Union would ordinarily condemn in high moral terms and even consider punishing. But that was not so easy this time. The nation in question was one of its own: Spain.

The Catalan situation has put the European Union and its members in an awkward position. The bloc defends the fundamental democratic rights of free speech and free assembly and of individuals to vote.

But while the European Union may be a union of democratic states, it is also, first and foremost, a union of sovereign states. It is wary of encouraging separatist forces that threaten to tear at many of the countries within it, as well as at the very fabric of the bloc.