You might have received a WEA alert before, perhaps for an AMBER Alert about a child abduction or as a notice about a local weather emergency, such as a tornado warning. And you’ve probably seen or heard an alert on the television or radio before—especially if you were alive before cable, DVR, and streaming services made television viewable on your own schedule. It used to be called the Emergency Broadcast System (EBS), which was established in 1963 and which replaced CONELRAD, first brought online in 1951 to notify the public in the event of a Soviet attack during the Cold War. In 1997, the system gained the ability to reach broadcasting methods beyond over-the-air signals, such as cable, fiber, and satellite, and became known as EAS.

But by the 2000s, mobile phones were beginning to become universal. Faced with criticism for how the government handled notification and response during Hurricane Katrina, a new system was established, called the Integrated Public Alert and Warning System (IPAWS). IPAWS made multiple government warning systems interoperable. 2006’s Warning, Alert, and Response Network Act allowed carriers and manufacturers the ability to let their subscribers opt out of the alerts, “other than an alert issued by the President.” The fact that many do so only emphasizes how much today’s citizen chafes at unwanted disruption, and how much official, governmental communications have been downplayed in favor of personal or commercial ones.

Both EBS and EAS were expressly designed to allow the president of the United States to deliver a message to the American people in the event of a national crisis or catastrophe. But then the Cold War ended, and the idea of nuclear calamity dissipated, and the emergency-notification systems became nuisances, mostly. For decades, people interacted with the system almost exclusively through its mandated tests (This is a test of the Emergency Broadcast System. This is only a test.) and the occasional television or radio notice, usually about severe weather.

The internet broke emergency alerts.

Today’s message was also a test—the first national test of the WEA system since its inception, as mandated by the IPAWS Modernization Act of 2015, which requires such a dry run to be conducted at least every three years.

There’s good reason to test the system. This January, a false alarm in Hawaii sent notice of a “BALLISTIC MISSILE THREAT INBOUND TO HAWAII” to smartphones. A similar but more detailed message was sent to broadcast media, thanks to the integrated IPAWS system. But there was no missile. The message was sent in error amidst a set of tests during a routine shift change. As a result, millions of Hawaiian residents and visitors were convinced that they had met their doom.

Other, less serious confusion about government notice in the age of the smartphone abounds. In addition to the national WEA system, many municipalities operate opt-in, text-message notification services for emergencies, traffic, and other civic inconveniences. On August 27, the system in Washington, D.C., called AlertDC, sent a notice to all its subscribers about a “Presidential Proclamation on the Death of Senator John Sidney McCain III.” The message was sent after the White House instructed federal offices to fly their flags at half-staff to honor the life of McCain, who had died two days earlier. It was lengthy, signed with the president’s name, and marked with the military acronym FYSA, “For Your Situational Awareness.”