Mo. Rev. Stat. ยง 26.030
Governor may veto appropriations โ extent โ exceptions.
26.030. Governor may veto appropriations โ extent โ exceptions. โ The governor may veto any item or portion of any item of any appropriation bill or the whole thereof; except that the governor shall not reduce any appropriation for free public schools or for the payment of principal and interest on the public debt.
(RSMo 1939 ยง 10905, A.L. 1945 p. 1428 ยง 58, A.L. 1959 H.B. 121) See also Const. Art. IV ยง 26.