Iowa Constitution Art. III, § 16. Executive approval--veto--item veto by governor

Every bill which shall have passed the general assembly, shall, before it becomes a law, be presented to the governor. If he approve, he shall sign it; but if not, he shall return it with his objections, to the house in which it originated, which shall enter the same upon their journal, and proceed to reconsider it; if, after such reconsideration, it again pass both houses, by yeas and nays, by a majority of two thirds of the members of each house, it shall become a law, notwithstanding the governor's objections. If any bill shall not be returned within three days after it shall have been presented to him, Sunday excepted, the same shall be a law in like manner as if he had signed it, unless the general assembly, by adjournment, prevent such return. Any bill submitted to the governor for his approval during the last three days of a session of the general assembly, shall be deposited by him in the office of the secretary of state, within thirty days after the adjournment, with his approval, if approved by him, and with his objections, if he disapproves thereof.

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.