Mo. Const. art. VI, § 19(a)

Any city which adopts or has adopted a charter for its own government, shall have all powers which the general assembly of the state of Missouri has authority to confer upon any city, provided such powers are consistent with the constitution of this state and are not limited or denied either by the charter so adopted or by statute. Such a city shall, in addition to its home rule powers, have all powers conferred by law. [Effective - 04 Nov 1971 , see footnote]