Questione giuridica chiave
Whether supplementary benefits must reduce the cantonal insurance-premium and savings-interest deduction under Thurgau tax law consistent with tax harmonization law.
Decisione estratta
Only the portion of premiums actually borne by the taxpayer may be deducted; the deduction must be reduced by tax-free supplementary benefits that reimburse the same insurance costs.
Motivazione estratta
Art. 9 Abs. 2 lit. g StHG requires the cantons to allow the deduction for actual insurance and savings-interest expenses, while only the maximum amount may be capped cantonally. Because supplementary benefits are tax-free and serve to cover health-insurance premiums, no deduction is available to the extent those premiums were reimbursed; otherwise there would be no effective expense borne by the taxpayer.