Here, the Financial Times tells it like it is:
North Korea's probable test of a nuclear weapon on Monday has triggered the second nuclear crisis in 13 years on the Korean peninsula.
In 1993, North Korea announced it would pull out of the Nuclear Non-Proliferation Treaty, leaving it free to divert nuclear material from its energy reactors to make a nuclear weapon and setting off a round of crisis diplomacy led by the Clinton administration. The result was the so-called agreed framework, which - in return for supplies of fuel oil to North Korea - froze most aspects of Pyongyang's nuclear weapons programme for the rest of the decade.
The agreed framework was in effect consigned to history when the Bush administration came to power in 2001. The new administration argued that although the road to a plutonium-based nuclear bomb had been frozen, the North Koreans were cheating by attempting to develop a uranium-based bomb that was not explicitly addressed by the agreement.
That five years later, North Korea has tested a nuclear weapon will be widely interpreted as a sign of the failure of the tougher approach favoured by the Bush team.
North Korea told the Security Council that it tested a weapon over the weekend. It must have been an underground test, which means every advanced nation on the earth heard the rumble. It's not exactly a claim the North Koreans can fake.