Very frightening. If they pull it off, it'll prove that they are too close for comfort to ICBM capability.
That was one of the main purposes of Sputnik 1. Not just for bragging rights and the psychological impact of an untouchable enemy satellite, but solid proof that they were close to being able to drop a payload anywhere on the planet.
They will aim for a) successful rocket stage separation; b) increased trajectory accuracy and distance; c) Western Pacific Ocean west of Hawaii, probably missile final remnants or dummy payload to come down somewhere between Midway Islands and the furthest western islands (small) of the Hawaiian chain, but in international waters. They necessarily have to launch over Japan (northern area) which will mobilize our guys and Japanese Self Defense Forces, Japan will be placed on alert and ready with PAC-3 missiles to shoot it down if it threatens Japan here. Of course, the North Koreans will say that this is not a ballistic missile test, but a satellite, and they will lie that their keen little Gwangmyeonson III satelitte is in earth orbit when it will be easy through NORAD and other sources to know they have done no such thing.
And what will Obama do?
Maybe send Jimmy Carter or Madeline Albright or Bill Richardson to appease them with something of value.
DPRK TV announcement they are going to launch on or around April 15th to celebrate Kim Il Sung's birthday.
Previous Taepodong II launch by North Korea.