Whenever the governor transmits to the president pro tempore of the senate and the speaker of the house of representatives his written declaration that he is unable to discharge the powers and duties of his office, and until he transmits to them a written declaration to the contrary, such powers and duties shall be discharged by the lieutenant governor, or if there be no lieutenant governor, by the president pro tempore of the senate, the speaker of the house, secretary of state, the state auditor, the state treasurer, or the attorney general in succession, as acting governor. Whenever a majority of a disability board comprised of the lieutenant governor, the secretary of state, the state auditor, the state treasurer, the attorney general, president pro tempore of the senate, the speaker of the house of representatives, the majority floor leader of the senate, and majority floor leader of the house, transmits to the president pro tempore of the senate and the speaker of the house of representatives their written declaration that the governor is unable to discharge the powers and duties of his office, the lieutenant governor, or if there be no lieutenant governor, the president pro tempore of the senate, the speaker of the house, the secretary of state, the state auditor, the state treasurer or the attorney general in succession, shall immediately assume the powers and duties of the office as acting governor. Thereafter when the governor transmits to the disability board his written declaration that no inability exists, he shall resume the powers and duties of his office on the fourth day after he transmits such declaration unless a majority of the disability board transmits their written declaration that the governor is unable to discharge the powers and duties of his office to the supreme court within that four day period, and the supreme court shall then convene to decide the issue. If the supreme court within twenty-one days after receipt of such declaration, determines by a majority vote of all members thereof that the governor is unable to discharge the powers and duties of his office, the acting governor shall continue to discharge the same as acting governor; otherwise, the governor shall resume the powers and duties of his office.