The so-called "mini-nukes" have a potency of less than five kilotons of explosive, a third of that contained in the bomb that the United States dropped on the Japanese city of Hiroshima in 1945, during the Second World War.
"If warfighters believe that a nuclear weapon is ‘small’ enough to ‘contain’ collateral damage, they are more likely to fire them, which means an environmental and humanitarian disaster we haven’t seen since World War II," expert Robert K. Musil told Tierramérica.
"That’s why we can say that there really is no such thing as a mini-nuke," argues Musil, director of the non-governmental Physicians for Social Responsibility, winner of the 1985 Nobel Peace Prize for its campaigns against nuclear testing.
The research, design and economic studies of these mini-bombs were approved by the US Congress as part of the national defense budget for 2004, after the Senate in May 2003 overturned the Spratt-Furse amendment, enacted 10 years ago to restrict them.
However, engineering development, production and testing of these explosives are still banned.
Experts note that the White House initiative does not violate the Non-Proliferation Treaty, the international agreement to eliminate nuclear weapons, because the text does not prohibit the development of new types of these arms.
However, for Wolfgang K.H. Panofsky, former director of the Stanford University Linear Accelerator Centre, this armament strategy could have considerable negative political impacts.
"The United States should take the lead in de-emphasizing dependence on nuclear weapons. These are the great ‘equalizer’ between relatively weak and strong states. Therefore the United States has most to lose from nuclear proliferation," he said in a Tierramérica interview.
The defenders of this weapon a small nuclear charge carried in the rear of a missile say that some military targets can only be destroyed with atomic-strength arms.
Among the advantages of smaller nuclear charges, say their defenders, is that they cause less "collateral damage" (civilian deaths and injuries, and radioactive contamination), and allow better control and lower maintenance costs.
The US Department of Defense is specifically interested in studying the use of small nuclear bombs, known as "earth penetrators", to destroy underground refuges used by potential enemies to store chemical and biological weapons, considered the greatest security threats of the new century.
This sort of installation would be buried under by dozens or hundreds of meters of solid rock, concrete or other material, protecting them from attack by conventional weapons.
According to a report presented to the US Congress, the CIA (Central Intelligence Agency) believes there are more than 1,400 strategic underground targets worldwide.
All nuclear arms on reserve have been tested with low levels of kilotonnage, says David Wright, co-director of the Global Security Program of the non-governmental Union of Concerned Scientists.
In his view, there are two likely motives behind the US weapons initiative. "There is a strong desire by the nuclear arms laboratories, like the Lawrence Livermore National Laboratory and Los Alamos National Laboratory, to design new arsenals, to embark on a new mission," he said in a conversation with Tierramérica.
Furthermore, says physicist Wright, the George W. Bush administration believes that the nuclear arms that his country has are too big to be used in the battlefield, undermining the credibility of a threat of US nuclear attack.
According to that argument, a less powerful weapon could have a much greater dissuasive effect on terrorists or enemy states.
There is a belief in Congress, says Wright, that we need these weapons to destroy chemical and biological arsenals buried underground. However, studies prove the inability of the small bombs to destroy those agents in underground installations. On the contrary, they help disperse them.
One of the experts’ concerns is that the mini-nukes should achieve a deep penetration in the ground, enough to explode, destroy the target and seal off the rubble produced at the point of explosion.
Wright estimates that a one-kiloton weapon would have to penetrate at least 60 meters below ground in order for the nuclear explosion to be contained. But with existing technology, such bombs could only go 10 meters deep.
At a depth of 15 meters, a one-kiloton explosion would knock down homes within a radius of one kilometer, killing most inhabitants, states a study by Physicians for Social Responsibility.
The survivors would absorb hundreds to thousands of rems of radiation, enough to be fatal. The rem is a unit used to measure the biological effects of radiation.
Even limited contact with radiation could affect the brain’s capacity to regulate blood circulation, reduce fertility and increase the incidence of cancer. Furthermore, DNA damage could give rise to genetic mutations in the offspring of affected populations.
For the survivors, discrimination and the refusal of medical treatment and employment could force them to keep their experience a secret, as occurred with many of the 280,000 Japanese who survived the nuclear blast in Hiroshima in 1945.
Because it is such a controversial issue, the fact that presidential elections loom in November mean that Bush, who seeks another term, is likely to put the matter on hold.
Wright predicts that the Bush administration is interested in restarting nuclear tests, but will not push for them until after the presidential elections in November if he wins.