A detailed look at the real nuclear launch process shows the U.S. president has only minutes to decide on retaliation during a nuclear attack, a system built for speed that leaves almost no room for error or second-guessing.

• The president's nuclear "football" briefcase carries launch codes and strike options, but authentication depends on a small card the president must find and read within minutes of being woken up.
• Submarine-launched missiles can hit the U.S. in as little as 10 minutes, leaving a 6-minute decision window once an attack is detected, so the system is built to act fast rather than carefully.
• Past false alarms, like a 1995 Russian radar mistaking a research rocket for an attack and a 1979 U.S. computer glitch, show how close the world has come to a mistaken launch.
• Military simulations suggest that even a "limited" nuclear exchange between major powers would still kill tens of thousands immediately and risk spiraling into a full-scale war within hours.
• A full nuclear exchange between major powers could kill over 100 million people in the first day and billions more over time from nuclear winter and crop failures, with no country's missile defenses able to stop a large-scale attack.

Outlook: Nuclear arsenals and decision systems remain built for rapid retaliation rather than careful deliberation, meaning the biggest ongoing risk is a false alarm or miscalculation rather than a deliberate first strike.