Emergency rule

A government or division of government (i.e. on a municipal, provincial/state level) may declare that their area is in a state of emergency. This means that the government can suspend and/or change some functions of the executive, the legislative and/or the judiciary during this period of time. It alerts citizens to change their normal behavior and orders government agencies to implement emergency plans. A government can declare a state of emergency during a time of natural or human-made disaster, during a period of civil unrest, or following a declaration of war or situation of international/internal armed conflict. Justitium is its equivalent in Roman law, where the Senate could put forward a final decree (senatus consultum ultimum) that was not subject to dispute.

It can also be used as a rationale (or pretext) for suspending rights and freedoms guaranteed under a country's constitution or basic law. The procedure for and legality of doing so varies by country.

Under international law, rights and freedoms may be suspended during a state of emergency; for example, a government can detain persons and hold them without trial. All rights that can be derogated from are listed in the International Covenant for Civil and Political Rights. Non-derogable rights cannot be suspended. Non-derogable rights are listed in Article 4 of the ICCPR, they include right to life, the rights to freedom from arbitrary deprivation of liberty, freedom of slavery and to freedom from torture and/or ill-treatment.

Some countries have made it illegal to modify emergency law or the constitution during the emergency; other countries have the freedom to change any legislation or rights based constitutional frameworks at any time that the legislative chooses to do so. Constitutions are contracts between the government and the private individuals of that country. The International Covenant for Civil and Political Rights (ICCPR) is an international law document signed by states. Therefore, the Covenant only applies to persons acting in an official capacity, not private individuals. However, signatories to the Covenant are expected to integrate it into national legislation. The state of emergency (within the ICCPR framework) must be publicly declared and the Secretary-General of the United Nations must be contacted immediately, to declare the reason for the emergency, the date on which the emergency is to start, the derogations that may take place, with the timeframe of the emergency and the date in which the emergency is expected to finish. Although this is common protocol stipulated by the ICCPR often this is not strictly followed; enforcement is better regulated by European Convention of human rights.

...
Wikipedia