On Wednesday, as Americans along the East Coast warily watched the progress of Hurricane Dorian, observers across the country noted something else with alarm.

When President Trump held up a map of Hurricane Dorian’s projected path, it included a Sharpie-drawn extension to show the storm hitting Alabama — an apparent attempt to defend an incorrect tweet he posted on Sunday, which claimed that Alabama was one of the states in the path of the storm. In fact, the National Hurricane Center did not, at any point, include Alabama in its forecast for where Dorian would fall. (Alabama did appear on a map of the probability of tropical storm conditions, but with low likelihood of actually seeing those conditions, according to the Washington Post.)

As was quickly pointed out, it is against the law to publish a falsified official weather forecast:

“Whoever knowingly issues or publishes any counterfeit weather forecast or warning of weather conditions falsely representing such forecast or warning to have been issued or published by the Weather Bureau, United States Signal Service, or other branch of the Government service, shall be fined under this title or imprisoned not more than ninety days, or both,” states the 1948 regulation on false weather reports. The current law applies to the National Oceanic and Atmospheric Administration’s National Weather Service (NWS), the government agency that provides weather forecasts and reports across the country (formerly known as the Weather Bureau).

But why does such a law exist in the first place?