Kernrechtsfrage
Whether the federal appeal could be used to attack the St. Gallen judgment as a vehicle for reviewing other cantons' final assessments in an intercantonal double-taxation dispute.
Extrahierter Entscheid
No. Because St. Gallen itself no longer raised a double-taxation issue, the appellant could not use that canton’s proceedings to reopen the other cantonal assessments.
Extrahierte Begründung
Under the BGG, the cantonal instances must be exhausted in at least one canton whose decision actually presents the double-taxation conflict. A decision from a canton with no remaining double-taxation issue cannot serve as a gateway to review final decisions of other cantons.