To the extent that an issuer has entered into an agreement, covenanted, or acted to assure that interest on its obligations is not included in the gross income of the recipients for federal income tax purposes pursuant to this chapter, the State will not limit or alter the power to perform the agreement or covenant or take action or in any way impair the rights and remedies of any holders, until the bonds, together with the interest on the bonds, and all costs and expenses in connection with any action or proceeding by or on behalf of the holders, are fully paid and discharged. Issuers are hereby authorized to include this pledge and agreement of the State in any agreement with the holders of their respective obligations.
32 V.S.A. § 997