Section 10. Veto power. (1) Each bill passed by the legislature, except bills proposing amendments to the Montana constitution, bills ratifying proposed amendments to the United States constitution, resolutions, and initiative and referendum measures, shall be submitted to the governor for his signature. If he does not sign or veto the bill within 10 days after its delivery to him, it shall become law. The governor shall return a vetoed bill to the legislature with a statement of his reasons therefor.

(2) The governor may return any bill to the legislature with his recommendation for amendment. If the legislature passes the bill in accordance with the governor's recommendation, it shall again return the bill to the governor for his reconsideration. The governor shall not return a bill for amendment a second time.

(3) If after receipt of a veto message, two-thirds of the members of each house present approve the bill, it shall become law.

(4) (a) If the legislature is not in session when the governor vetoes a bill approved by two-thirds of the members present, he shall return the bill with his reasons therefor to the secretary of state. The secretary of state shall poll the members of the legislature by mail and shall send each member a copy of the governor's veto message. If two-thirds or more of the members of each house vote to override the veto, the bill shall become law.

(b) The legislature may reconvene as provided by law to reconsider any bill vetoed by the governor when the legislature is not in session.

(5) The governor may veto items in appropriation bills, and in such instances the procedure shall be the same as upon veto of an entire bill.