Plot hole: McKittrick says the computer will not accept the launch codes unless they are at DEFCON 1. At the end of the climax the computer is trying to guess the code while they are at DEFCON 1. So why couldn't they just go back to a different DEFCON before the correct code was guessed?
Plot hole: Given the number of possible combinations the launch code could be (over 3600 trillion possibilities) it makes no sense that W.O.P.R cannot process that significantly quicker given how easily it's able to calculate thousands of ICBM impacts, damage inflicted, casualties, etc. for each "War Scenario" at the end as quickly as it does to determine a winner.
jerimiah
Answer: They were erroneously alerted that an actual nuclear attack was underway, and they had been trained to respond by firing a nuclear warhead. However, one was unconvinced that the US was actually under attack, and he wanted further confirmation from his superiors. The other insisted that they follow protocol and fire the missiles. One man alone cannot launch the missiles, it takes two, and the one with the gun is attempting to force his partner to follow through on launching the weapon.
raywest