Several factors – all driven by Pyongyang – are at work and have created an increasingly tense military situation on the peninsula. Additional long-range missile tests are expected, and naval clashes along the Northern Limit Line (NLL) are becoming more likely.
Political
Some background: In January 2009, North Korea “voided” all political-military agreements with [...]

That someone in the administration recognizes the absurdity of engaging in Ground Hog Day deals with North Korea (and is publicly commenting about it) is somewhat encouraging. Robert Gates, U.S. Secretary of Defense, recently had this to say about North Korea:
“We will not stand idly by as North Korea builds the capability to [...]

The title assumes North Korea did test a nuclear device, which I think likely, and not an equivalent amount of TNT, initially thought a possibility in 2006 until radioactive isotopes of krypton and xenon were detected.
There are several reasons for a North Korea to conduct a nuclear test and it’s difficult if not impossible [...]

Update, North Korea’s announcement: Full text of the Korean Central News Agency (KCNA) announcement of the nuclear test, presumably a TV broadcast (via the Independent):
“The Democratic People’s Republic of Korea successfully conducted one more underground nuclear test on May 25 as part of the measures to bolster up its nuclear deterrent for self-defence in [...]

The Taepo Dong 2 (TD-2) (대포동 2호) missile launch(es) North Korea likely is preparing for, and recent voiding of all political-military deals with South Korea, are part of Pyongyang’s long-term strategy of regime survival. While these actions also have less important near-terms goals – expressing displeasure with ROK President Lee Myung-bak’s relatively hard-line approach [...]

NightWatch has an interesting analysis of a statement issued by North Korea yesterday, which, “carries a credible threat of incidents at sea off the west coast, but omits many of the usual terms of threat.”

In mid-2008, North Korea turned over 18,000 pages of documents to U.S. officials to help prove it was telling the truth about its record of plutonium processing. Ironically, those documents had trace amounts of highly enriched uranium (HEU) that was likely not possible transfer from Pakistani equipment obtained via A.Q. Khan. The North [...]

In 1999 the news on North Korea was both alarmist over North Korean antics and naively hopeful of peace suddenly breaking out. A decade later the news is still often alarmist - North Korea did test a nuclear device in 2006 after all - but less naive after decade of reneging on agreements and [...]

Via the AP: “Vice President Dick Cheney says North Korea helped Syria build a reactor at a site that Israel suspected of being a nuclear installation and bombed in 2007. The White House has alleged North Korean involvement before, but top Bush administration officials have said little publicly on the issue, which is still [...]

The trouble with North Korea is that nobody wants it — except the current ruling elite of North Korea itself.
In a previous post, I rather immodestly predicted that, should the Kim regime collapse in North Korea, a military junta backed by China would emerge, resulting in a Burma-ization of North Korea. I further speculated that [...]