You are in a panic;
Everyone around you is in a panic;
The target may not be moving simply in a single dimension, it may be moving in two or more dimensions, and it is constantly changing form;
You are not sure whether the object that you have identified as the target is, indeed, the target at which you should be shooting; and
The President and majorities in both the House and the Senate must agree that the time has arrived for you to pull the trigger.