That is why it is key for the US as quickly as possible to get laser weapons to defend against missile attacks from N Korea, Iran, Russia or whoever.  Not only are US missiles just a little more than 50% successful in interception, each missile cost over $1 million or more.  Laser energy blasts are much, much cheaper and while missiles can fly around 6-7 times the speed of sound, light travels at 900,000 times the speed of sound, greatly improving its ability to intercept and stop incoming missiles from reaching its targets.