How would the president “push the button” for a nuclear attack?

As depicted in some spy movies, the president would not press a button; he would make a phone call.

To begin a nuclear attack, the president telephones the commander in chief at the Strategic Air Command in Omaha, Nebraska; several officers at SAC would verify the president’s orders.

Once verified, instructions would go to bomber and missile crews, who would enact a series of movements to arm the bombs.