One can have ideological blinders on and keep warning all and sundry about death raining down from above and drumming up fears about the silly mockups of ICBMs the DPRK government put on parade on the 100th anniversary of the birth of Kim Il-sung...or one can read Markus Schiller and Robert H. Schmucker.
Regarding the mockups:
"A Dog and Pony Show" (Link 1)
Regarding the internal structure and the engineering limits of purported ICBMs, if someone ever tried to build an actual missile looking like the ones paraded:
"The Assumed KN-08 Technology" (Link 2)
That "woof" sound you just hear after you finish reading the two papers is the editorial offices of the Sankei Shimbun undergoing spontaneous diurnal combustion.
Both papers come via the good graces of Dr. Jeffrey Lewis and Arms Control Wonk.