As expected on Thursday, Spain's Constitutional Court admitted a central government challenge to the Catalan independence referendum bill, the related electoral committee, and the decree calling the vote, a normal part of the constitutional challenge procedure, that does not constitute a ruling from the justices on the matter itself.

Exceptionally, however, the court also warned more than 1,000 authority figures in Catalonia that they have a duty to uphold the suspension or face possible criminal charges for not doing so.

The list included the First Minister, Carles Puigdemont, and al...