Mo. Rev. Stat. § 77.280: Mayor may veto resolutions and orders.

The mayor shall also have the power to veto any resolution or order of the council which calls for or contemplates the expenditure of the revenues of the city. Such vetoes shall be noted on the journal of the council, and shall be effective and binding unless the council, at a subsequent session thereof, general or special, shall pass said resolution or order by a vote of three-fourths of all the members elected to the council.