Alabama constitution
Article IV: legislative department
Section 100

No obligation or liability of any person, association, or corporation held or owned by this state, or by any county or other municipality thereof, shall ever be remitted, released, or postponed, or in any way diminished, by the legislature; nor shall such liability or obligation be extinguished except by payment thereof; nor shall such liability or obligation be exchanged or transferred except upon payment of its face value; provided, that this section shall not prevent the legislature from providing by general law for the compromise of doubtful claims.