The President as Commander in Chief can place the Philippines or any part of it under martial law or suspend the writ of habeas corpus “in case of invasion or rebellion, when the public safety requires it,” according to Article VII, Section 18 of the 1987 Constitution.
The 1935 Constitution also stipulates these same conditions in its martial law provision.
But there are now limits to the use of this power in the 1987 Constitution:
The President is required to submit a report in person or in writing to Congress within 48 hours from the proclamation of martial law.
Congress, in turn, voting jointly, by a vote of at least a majority of all its members in regular or special session, may revoke such proclamation or suspension, which revocation shall not be set aside by the President.
The period of martial law cannot exceed 60 days.
Unlike in Marcos’ martial law powers, the President cannot suspend the Constitution, close Congress nor supplant the civil courts. The Constitution states: A state of martial law does not suspend the operation of the Constitution, nor supplant the functioning of the civil courts or the legislative assemblies, nor authorize the conferment of jurisdiction on military courts and agencies over civilians where civil courts are able to function, nor automatically suspend the privilege of the writ.
The Supreme Court “may review, in an appropriate proceeding filed by any citizen, the sufficiency of the factual basis of the proclamation of martial law or the suspension of the privilege of the writ or the extension thereof, and must promulgate its decision thereon within 30 days from its filing.” Inquirer Research
Source: 1987 Constitution