Questione giuridica chiave
Whether the direct constitutional complaint against the Zürich tax domicile decision was admissible without exhausting cantonal remedies.
Decisione estratta
The complaint was admissible because a tax domicile decision raising double-taxation concerns may be challenged directly before the Federal Supreme Court.
Motivazione estratta
In double-taxation cases, direct constitutional review is available; subsidiarity does not bar the remedy, and the right to challenge the already final Graubünden assessment within the complaint period also extends review to that assessment.