The A.R.G.U.S. Key was created shortly after the formation of A.R.G.U.S. following Darkseid's invasion of Earth. It was only the formation of the Justice League that saw the forces of Apokolips being defeated. In the aftermath, A.R.G.U.S. was created under orders from the President of the United States of America. The organization was intended to support the superheroes efforts but it was also meant to monitor them in case the Justice League ever went rogue. Afterwards, the organization was established with many facilities and staff to support them. This saw the creation of the A.R.G.U.S. Key that allowed the tracking of all their facilities and access to the more restricted installations. These included the Black Room, Red Room, Green Room, the Circus and the Wonder Room. The Key itself was kept in the care of the American President and only used in the most extreme of circumstances.
During the events of Forever Evil, the Crime Syndicate was responsible for seemingly killing the Justice League. This saw the Secret Society of Super-Villains attempting to take control of the now vulnerable world. Among the survivors was Steve Trevor who headed A.R.G.U.S. and after the decimation of their headquarters he decided to retrieve the Key. At this point, the Secret Society was attacking the White House in order to take the President hostage. Trevor and a team were dispatched to rescue the President where he used it to put the Commander-in-Chief into the Green Room for safety. With the Key, Steve later gained access to the Wonder Room in order to consult the Delphi Mirror on Wonder Woman's fate.
He later used the key to open the Circus after it went into lockdown during the Crime Syndicate's control of the planet. This allowed Trevor to meet A.R.G.U.S. agent Dale Gunn who provided him a telepath that allowed him to determine the means in finding Wonder Woman which was the Lasso of Truth that was in Cheetah's hands.