Jennifer:  "(Trump's former rival for the Republican presidential nomination, Marco Rubio, said the United States could not trust "the nuclear codes" to an "erratic individual.")"  Neither Rubio nor yourself understand how the "football" works.  The president can't simply enter the "codes" and start a nuclear war.  The military must first detect a verified attack upon the U.S., or upon any of our allies.  Then they notify, through the chain of command, the president.  The military will make recommendations to the president, who will then only approve any, or all of them.  DEFCON status, mobilization, and nuclear release is tightly controlled through checks and balances.  If all of the civilian leadership is incapacitated, or can't be reached because of destruction of our communications, then the military has written guidelines which directs any response to the attack.  If the president goes "nut-case" and just enters the codes, he will be ignored, per written SOP's.