In January North Korea conducted its fourth nuclear test in the face of universal international protest. Even China, Pyongyang's one nominal ally, joined in the criticism.
With Beijing's support the United Nations imposed new sanctions on North Korea. The United States, South Korea and Japan warned Pyongyang of further isolation if the North continued to flout the will of the international community.
Now the North appears to be preparing another nuclear test. If Pyongyang does so no further proof will be needed that the North intends to become a significant nuclear power.