Mothers, your children are in danger! I will protect them. Vote for me." From burning witches in the Middle Ages down to Hitler's gas ovens, we can trace the overtly murderous variety of political fear-mongering.
But even in apparently benign forms, scare stories can have dire consequences.
Consider the political fright-merchants for our age - the Greens. A visit to the New Zealand Greens' website throws up ordinary aspects of modern life the worldwide Green movement views as dangerous.
Cellphones: Despite repeated studies showing them safe and despite the fact that they have saved the lives of countless lost trampers, sinking boaties and bleeding road-accident victims, the Greens would have us fear cellphones and their towers.
Fluoridation: Sure it stops tooth decay, with its associated agonies and expense. But the Greens worry that it may affect the brain and increase rates of cancer.
Pesticides: Greens have long tried to associate pesticides with cancer. Now they support the imaginative complaint of a Tauranga headmaster that pesticide sprays are adversely affecting behaviour of his students.
The Greens' doom scenarios have been proved rubbish. Overpopulation has not caused general famine, population growth rates are falling, the world is awash with food surpluses, and plant and animal species are not going hugely extinct. More synthetic chemicals than ever surround us, but adjusted cancer rates are falling.
The Greens' anti-technology arguments could have been used to block the introduction of electric power over a century ago.
Could electricity be proved safe? No. Electricity kills easily and often. Would the production of it be environmentally sound? No. Hydro dams and coal generators were bound to degrade the environment.
Would electricity encourage people to maintain their familiar traditions, quiet evenings reading by the whale-oil lamp? No. Whale oil, lighting gas and kerosene, and the firms that supplied them, were wiped out by electricity.
The Green movement is now turning its phobic Luddite mindset to one of the greatest gifts science offers the coming century - agricultural biotechnology.
Contrary to Green mythology, natural organic foods are not intrinsically safe. Many plants contain poisons and carcinogens such as the alkaloids in greened potatoes or oxalates in rhubarb leaves that evolved to sicken predators, such as humans, who eat them.
Biotech promises to minimise natural toxins in foods while enhancing their beneficial qualities, including giving fruits and vegetables better flavour.
Even at this early stage of its development, genetically engineered golden rice can provide enough vitamin A to prevent blindness in malnourished Third World children.
Biotech can clean up agriculture. GM has almost cut in half the pesticides required to grow cotton in Australia and elsewhere; chemical-pesticide avoidance is a major aim of biotech.
Productivity can be increased, too, important in such places such as South America, where the introduction of GM crops can obviate the need to fell more rainforest.
Just as important will be the development of varieties that will grow well in harsh conditions in the Third World such as in arid lands with high salinity. Which brings us to southern Africa, now facing a drought and possible famine.
The United States is supplying about half the area's food relief in the form of maize for about 13 million people in Lesotho, Malawi, Mozambique, Swaziland, Zambia and Zimbabwe.
In these areas, the death rate attributable to famine conditions is perhaps 2000 to 3000 children a day.
But there's a problem. Although the maize being given to these countries is eaten not only in the US but also in China, India, Argentina and Canada, the Green idea that GM food is a health threat has got through to a few African leaders.
Persuaded by European Green propaganda, the Zambian President, Levy Patrick Mwanawasa, told the Sustainable Development Summit: "We would rather starve than get something toxic. Just because my people are hungry does not mean that I can give them poison."
While admitting that Zambians had been eating such maize for the past six years, Mwanawasa argues that nobody has proved that GMOs pose zero risk and therefore the importation of it must be halted.
The situation is grotesque: at this moment millions of people in rich countries happily munch their way through genetically engineered food products. No one is being harmed except by the resulting obesity.
Meanwhile, malnourished African children die in their thousands - maybe two or three since you started reading this column. Some of these deaths can be laid directly at the feet of the Green scaremongers who convinced African officials that American food aid was unsafe.
Scare stories do work for the Greens. I know a lovely young mother who told me she voted for the Greens because "they care about the future". She worries about toxins poisoning her children, all those biotech Frankenfoods.
Her children are healthy Kiwi kids and she has nothing to worry about. Still, a mother's natural anxiety, played on by the Greens, determines her vote.
But as a byproduct of Green electioneering in the rich countries, an African mother watches her child die. Of course, the African mother can't vote in Germany or New Zealand, so the Greens sit safe.
But I won't let them forget: They have blood on their hands.
* Associate Professor Denis Dutton teaches the philosophy of art at Canterbury University and is editor of Arts & Letters Daily.
* John Roughan is overseas.