Initially conceived as a form of emergency population warning, these broadcasts are often of a political nature, as most of them are messages by governmental authorities about various topics of general interest.
In some countries, including Argentina and Venezuela, all stations are mandated to air these messages (similar in nature to Emergency Action Notifications in the United States).
[6] The Brazilian Communication Company (EBC) is tasked with handling the taping and live broadcast of cadeia nacional addresses, which are prepared by the Secretary of Government.
Free-to-air television networks are required by law to broadcast these addresses live, thus temporarily interrupting their scheduled programming.
[8] Since Chile's return to democracy in 1989, most cadenas nacionales have been voluntary in nature, but under previous governments such as those of Augusto Pinochet and Salvador Allende, stations were obliged to carry these messages.
The Organic Communication Law's article 74 replaced it, retaining the requirements for broadcasters and extending them to pay television services, which must suspend their own program transmissions to carry cadenas.
[3] The Telecommunications Law of 1997 requires stations to transmit cadenas, which may be called for by the president "in case of war, invasion of territory, rebellion, sedition, catastrophe, epidemic or other calamity, grave disturbances of the public order or messages of national interest".
[3] Cadenas nacionales are obligatory for all television and radio stations, and are used to broadcast presidential reports and messages of national interest.
[13] Approved in 2004, the Law on Social Responsibility on Radio and Television (Ley RESORTE) requires broadcasters to transmit cadenas nacionales.
This provision has only been used once, in order to mandate the broadcast of a speech by Prime Minister Jean Chrétien on October 25, 1995 (prior to the Quebec independence referendum) by the licensed television networks.
In 2017, Bell Media attempted to request an invocation of the law in order to effectively override a CRTC decision suspending its "simsub" regulations (requiring pay television providers to replace feeds from U.S. terrestrial broadcasters if they carry the same programming as a local terrestrial broadcaster, in order to protect Canadian advertising revenue) for the Super Bowl.
[14][15] Forced cadenas nacionales of a political nature have been strongly criticized by some media outlets, as in some cases it requires them to broadcast opinions that differ from their normal editorial stances.
[19] In Argentina, the frequent use of cadenas by Cristina Fernández de Kirchner during her presidency has been compared to "abuse" of the system by the opposition.