If there is another armed conflict on the Korean peninsula, it's unlikely an Australian government would feel bound by historical precedent or outdated legal instruments.
It's likely there was indeed no successful re-entry on the North Korean test, but that should not be immediately interpreted as a setback for the program.
A world in which Japan and South Korea have less trust in America's ability and willingness to defend them against North Korea is one that works to China's advantage.
Unlike its missile and nuclear programs, which North Korean leaders proudly parade and test, Pyongyang denies it possesses chemical weapons. So what are North Korea's capabilities?