Mass. Const. amend. art. XCI

Whenever the governor transmits to the president of the senate and the speaker of the house his written declaration that he is unable to discharge the powers and duties of his office, the office of governor shall be deemed to be vacant within the meaning of this Constitution.

Whenever the chief justice and a majority of the associate justices of the supreme judicial court, or such other body as the general court may by law provide, transmit to the president of the senate and the speaker of the house their written declaration that the governor is unable to discharge the powers and duties of his office, the office of governor shall be deemed to be vacant within the meaning of this Constitution.

Thereafter, in either of the above cases, whenever the governor transmits to the president of the senate and the speaker of the house his written declaration that no inability exists such vacancy shall be deemed to have terminated four days thereafter and the governor shall resume the powers and duties of his office unless the chief justice and a majority of the associate justices of the supreme judicial court, or such other body as the general court may by law provide, transmit within said four days to the president of the senate and the speaker of the house their written declaration that the governor is unable to discharge the powers and duties of his office. Thereupon the general court shall decide the issue, assembling within forty-eight hours for that purpose if not in session. If the general court within twenty-one days after receipt of the latter written declaration, or, if the general court is not in session, within twenty-one days after the general court is required to assemble, determine by a vote, taken by yeas and nays, of two thirds of each house present and voting thereon, that the governor is unable to discharge the powers and duties of his office, the office of governor shall continue to be deemed to be vacant; otherwise such vacancy shall be deemed to have terminated and the governor shall resume the powers and duties of his office.

If a vacancy in the office of governor, as described in this Article, continues for six months and if such six-month period expires more than five months prior to a biennial state election other than an election for governor, there shall be an election of governor at such biennial state election for the balance of the unexpired four-year term.

If a vacancy in the office of governor, as described in this Article, continues for six months and if such six-month period expires more than five months prior to a biennial state election other than an election for governor, there shall be an election of governor at such biennial state election for the balance of the unexpired four-year term.