Neb. Rev. Stat. § 39-2214

The state pledges and agrees with the holders of any bonds issued under the Nebraska Highway Bond Act that it will not limit or alter or in any way impair the rights and remedies of such holders until such bonds, together with the interest thereon, the interest on any unpaid installments of interest, and all costs and expenses for which the commission is liable in connection with any action or proceeding by or on behalf of such holders, are fully met and discharged.