Liberal and conservative risk assessment

Thirty years ago I wrote speeches for DuPont Company executives and sometimes dealt with risk assessment concerning public health. To take a simple example, let's say that lowering the speed limit on highways will save X-number of lives at a cost of Y billion dollars in terms of lower productivity and increased enforcement costs. We can only have zero risk of auto fatalities by never riding in a car-so how much risk will we accept, and what is an acceptable trade-off between travel and tragedy?

Back then liberals almost always wanted to minimize risk from new products, and business-oriented conservatives were willing to accept more risk. Now, in many economically developed countries, up to 250,000 of every 1 million persons are likely to die of cancer-one out of four persons. What if a new product or chemical is likely to make that number 250,001: Allow it or ban it? That's 300 lives in the United States. Should those be saved at a cost of $300 million? I suspect many of us would say yes. How about $300 billion?

I mention this now because a National Public Radio story on 9/11 raised the question of how much the United States should spend on homeland security when the number of people killed by terrorists worldwide is 400 per year. The apparently liberal academic analyst-this is NPR, after all-suggested that we are over-spending on what is terrible for those 400 but is not an "existential threat" to the country. It struck my wife and me that the lineup for this debate was the opposite of that which is common regarding occupational health and safety: Conservatives are willing to spend and perhaps overspend on threats from abroad; liberals are willing to spend and perhaps overspend on domestic concerns.

One difference is that terrorist attacks are sudden and often unexpected: Citizens will hold a political figure responsible if he has not spent enormous sums for protection. Cancer or environmental risks typically are silent and slow-developing, which means it's harder to assign blame. Or could it be that conservatives are more likely to think about original sin and therefore more likely to see purposeful human evil, while liberals are more likely to see man as good but harmed by a bad environment?