Kernrechtsfrage
Whether the tax assessments could be revised because they were based on an unconstitutional cantonal provision.
Extrahierter Entscheid
No. The earlier assessments remained final; the later finding of unconstitutionality did not by itself create a revision ground or render the assessments void.
Extrahierte Begründung
Final assessments are not reopened merely because the underlying rule was later found unconstitutional. Only especially grave defects causing nullity would do so, and the assessments were not issued in breach of a federal tax-exemption norm.