Mo. Rev. Stat. § 162.670
In order to fully implement Section 1(a) of Article IX, Constitution of Missouri, 1945, providing for the establishment and maintenance of free public schools for gratuitous instruction of all persons in this state within ages not in excess of twenty-one years as prescribed by law, it is hereby declared the policy of the state of Missouri to provide or to require public schools to provide to all handicapped and severely handicapped children within the ages prescribed herein, as an integral part of Missouri's system of gratuitous education, a free appropriate education consistent with the provisions set forth in state and federal regulations implementing the Individuals with Disabilities Education Act (IDEA), 20 U.S.C. Section 1400 et seq. and any amendments thereto. The need of such children for early recognition, diagnosis and intensive educational services leading to more successful participation in home, employment and community life is recognized. The timely implementation of this policy is declared to be an integral part of the policy of this state.
§ 162.670, RSMo