In Nigeria’s constitution, Section 305 lays out the procedure for proclamation of state of emergency in the whole federation or any part thereof. The president is empowered to issue the declaration by way of official gazette.
The state of emergency is however subject to the ratification by a two-thirds majority of the National Assembly within two days if the legislators are in session, or 10 days, if they are not.
Here’s what Section 305 says:
305(1) Subject to the provisions of this Constitution, the President may by instrument published in the Official Gazette of the Government of the Federation issue a Proclamation of a state of emergency in the Federation or any part thereof.
(2) The President shall immediately after the publication, transmit copies of the Official Gazette of the Government of the Federation containing the proclamation including the details of the emergency to the President of the Senate and the Speaker of the House of Representatives, each of whom shall forthwith convene or arrange for a meeting of the House of which he is President or Speaker, as the case may be, to consider the situation and decide whether or not to pass a resolution approving the Proclamation.
(3) The President shall have power to issue a Proclamation of a state of emergency only when:
(a) the Federation is at war;
(b) the Federation is in imminent danger of invasion or involvement in a state of war;
(c) there is actual breakdown of public order and public safety in the Federation or any part thereof to such extent as to require extraordinary measures to restore peace and security;
(d) there is a clear and present danger of an actual breakdown of public order and public safety in the Federation or any part thereof requiring extraordinary measures to avert such danger;
(e) there is an occurrence or imminent danger, or the occurrence of any disaster or natural calamity, affecting the community or a section of the community in the Federation;
(f) there is any other public danger which clearly constitutes a threat to the existence of the Federation; or
(g) the President receives a request to do so in accordance with the provisions of subsection (4) of this section.
(4) The Governor of a state may, with the sanction of a resolution supported by two-thirds majority of the House of Assembly, request the President to issue a Proclamation of a state of emergency in the state when there is in existence within the state any of the situations specified in subsection (3) (c), (d) and (e) of this section and such situation does not extend beyond the boundaries of the state.
(5) The President shall not issue a Proclamation of a state of emergency in any case to which the provisions of subsection (4) of this section apply unless the governor of the state fails within a reasonable time to make a request to the President to issue such Proclamation.
(6) A Proclamation issued by the President under this section shall cease to have effect:
(a) if it is revoked by the President by instrument published in the Official Gazette of the government of the federation;
(b) if it affects the Federation or any part thereof and within two days when the National Assembly is in session, or within 10 days when the National Assembly is not in session, after its publication, there is no resolution supported by two-thirds majority of all the members of each House of the National Assembly approving the Proclamation;
(c) after a period of six months has elapsed since it has been in force:
Provided that the National Assembly may, before the expiration of the period of six months aforesaid, extend the period for the Proclamation of the state of emergency to remain in force from time to time for a further period of six months by resolution passed in like manner; or
(d) at any time after the approval referred to in paragraph (b) or the extension referred to in paragraph (c) of this subsection, when each House of the National Assembly revokes the Proclamation by a simple majority of all the members of each House.