Here are the actual physical and temporal limiting factors on presidential nuclear launch authority. 1/

1. POTUS needs to contact the NMCC or an alternate command post. This requires a phone number. These number are on speed-dial on the phones carried by the military aide and emergency action team from WHMO.

2. He could also ask a White House operator from Royal Crown, the secure switchboard to connect him. But he’d have to know exactly what to ask for. Not a big constraint - a tiny one.

3. Assuming POTUS connects to a commander center, he would be transferred to an Emergency Actions controller. By this point lots of other people would be notified that POTUS was trying to do something.

4. The controller would first ask for authentication. POTUS would be read aloud a series of alphanumeric as and challenged to provide the corresponding alphanumeric on the nuclear authentication card he carries.