Although there were suspicions in United States intelligence circles that North Korea was continuing to develop its nuclear weapons, one of the problems for US agencies was the way in which the North Korean regime had gone to ground.
Progressively, and over a period of at least two decades, the North Koreans had developed a huge system of underground facilities, some of them buried deep inside mountains. These were the locations used to undertake research and development into a range of weapons and missiles, and their purpose was both to deny foreign agencies information on what was happening and to ensure their security if it came to war.
Thus, this weeks news of North Koreas possession of a number of nuclear weapons is in itself not new, but it is seen as a substantial problem by the US armed forces as they seek the ability to counter any threat, from wherever they perceive it to come. It is one of the reasons why the United States is now starting to develop the worlds most powerful conventional bomb, a fifteen-tonne device that could be carried on an aircraft capable of delivering it anywhere in the world.
The dig/bomb race: bunkers versus bunker-busters
The use of underground facilities goes back several decades. During the second world war, Germany developed some of its early missiles in underground factories, and both the Soviet Union and the United States put many of their intercontinental nuclear missiles in underground silos and built deeply buried command centres.
This lesson was subsequently learnt by other countries, which saw themselves in potential conflict with the US or other powerful states. Iraq, for example, viewed Israel as the most likely enemy in the 1980s, especially after the Israeli raid on the Osiraq nuclear reactor in 1981. One of its responses was to build large numbers of heavily reinforced aircraft shelters as well as underground command bunkers.
The Iraqi armed forces had reckoned themselves capable of holding their own in a war with Israel, but were unable to resist a much larger coalition in 1991, led by the United States with all of its advanced military capabilities.
Even so, the US found it remarkably difficult to damage the most heavily-protected Iraqi facilities, a lesson which was not lost on Iraq after the war, or on other countries such as Iran, Syria and North Korea. According to a US army source in 1997:
Following the Gulf War, the number of deeply buried targets began to proliferate rapidly as countries around the world realized that going deep was the only way to protect their critical assets from our precision strike systems. Today, there are thousands of hard and deeply buried targets in countries such as Libya, Syria and North Korea. These hardened structures protect command and control centres, chemical and biological weapon production and storage facilities, rocket and missile launchers, and other high priority targets. Destruction and neutralization of these targets will be essential in any future conflict. (Quoted in Defense News, 6 October 1997.)
As a result, the last few years have seen the development of one of the weirdest arms races ever to be seen.
On the one side are a number of states, busily constructing ever deeper bunkers and weapons plants, and on the other side is the United States, intensively researching new kinds of conventional bunker-busters and even going so far as to modify its standard tactical nuclear weapon (the B61) to produce the worlds first earth-penetrating nuclear warhead (the B61-11).
This device, incidentally, may well be deployed, along with B-2 stealth bombers, to the US base on Diego Garcia in the Indian Ocean, for possible use against Iraq. Diego Garcia is a British territory leased to the United States, but the UK government has refused to state whether it is allowing the US to base nuclear weapons there, falling back on the well-tried neither confirm nor deny policy when asked questions on nuclear issues.
Echoes of Vietnam, augurs of Iraq
The so-called dig/bomb race between states wanting to protect their weapons and command centres, and the United States seeking to counter this trend, has accelerated in recent years, and this is what is now likely to lead to the construction of the worlds largest and most powerful bomb.
The background to this has an odd history. Back in the 1960s, the United States developed a number of weapons for use in the particular circumstances of Vietnam. These included area-impact munitions such as cluster bombs, which could have a devastating anti-personnel effect, but they also developed some very powerful conventional bombs that could be used against tunnels and other protected targets.
One of these devices was the BLU-82/B weapon known as Big Blue or Daisy Cutter. This is a 6.8 tonne bomb filled with ammonium nitrate, powdered aluminium and a polystyrene binding agent that, when detonated, produces a local effect almost as devastating as a small tactical nuclear weapon.
The bomb was used in Vietnam for various purposes, not least the instant clearing of rainforest to create helicopter landing-pads, and it was also used in the 1991 Gulf war against Iraqi trenches.
More recently, the BLU-82/B was used on a number of occasions in Afghanistan, including attacks on cave complexes at Tora Bora earlier this year. Journalists who visited the area later reported a shattered landscape akin to the effects of the mass bombardments on the Western front in the first world war.
From a US air force perspective, three problems have now arisen. The first is that they have very few of these thirty-five-year old bombs left and are not currently manufacturing any more. The second is that they can only be carried by a particular type of transport aircraft, the Hercules MC-130, that is relatively low-flying and susceptible to anti-aircraft artillery and missiles. The third is that other anti-bunker bombs recently developed are not able to destroy the most heavily protected targets.
One response to these problems is a plan to produce an entirely new and massive bomb, more than twice the weight of the old one and very much more devastating, given the modern high explosives that would be used. It would weigh nearly fifteen tonnes and is probably going to be developed in two forms.
One will be an earth-penetrator, designed primarily for use against underground targets, and will be at least six times as powerful as anything currently available to the air force. The other is a blast version for use against more dispersed targets at ground level.
One key difference with the bomb it replaces is that the new device will be capable of being deployed on the B-2 stealth bomber which can operate at high altitudes and is virtually impervious to air defences. With aerial refuelling and limited overseas basing (to Britain, Guam or Diego Garcia, for example) the B-2 would be able to use such a bomb against targets anywhere in the world. The US air force sees this as a key to gaining a lead in the dig/bomb race.
Moving the targets
As with all such arms races, though, it will have its consequences. If the United States does put much more effort into this kind of system, its potential opponents will simply revise their mode of operations. This might involve going even deeper underground or, more likely, dispersing many of their research, development and production facilities throughout their countries.
Furthermore, the opponents of the US will increasingly recognise that various forms of asymmetric warfare may be much more effective. Many of these tactics are currently used by sub-state groups such as al-Qaida and its many associates. In the last three weeks alone, for example, we have seen the targeting of a French oil-tanker off the coast of Lebanon, a devastating attack on western tourists in a Bali night club, the hostage-taking in Moscow with its disastrous aftermath, the attacks on US soldiers in Kuwait, and the killing of a US diplomat in Jordan.
From a US military perspective, new weapons such as the Big Blue II represent another way of helping to maintain control. In reality they are likely to form yet one more small part in the cycle of violence, making it even less likely that we begin to address the underlying problems that are producing a fractured and increasingly unstable world.