Iowa constitution
Article III
Section 16

The governor may approve appropriation bills in whole or in part, and may disapprove any item of an appropriation bill; and the part approved shall become a law. Any item of an appropriation bill disapproved by the governor shall be returned, with his objections, to the house in which it originated, or shall be deposited by him in the office of the secretary of state in the case of an appropriation bill submitted to the governor for his approval during the last three days of a session of the general assembly, and the procedure in each case shall be the same as provided for other bills. Any such item of an appropriation bill may be enacted into law notwithstanding the governor's objections, in the same manner as provided for other bills.