And yet there is close to zero public debate or discussion of the horrifying threat of nuclear arms. It's astonishing that people who don't trust government to administer a national health-care program, or who don't trust politicians to decide on the nation's top tax rate, seem to have unqualified and unthinking trust in the people and institutions that get us all killed, practically speaking, in a heartbeat.

Nuclear weapons are subject -- at least, I hope -- to the strictest controls known to humanity. And while we scoff at the doctrine of papal infallibility, we seem to accept without hesitation the notion that the command-and-control systems of the White House and the United States military are absolutely and perfectly failsafe. And if you have no doubts about America's systems, we are still at the mercy of command-and-control systems in Russia and in China -- systems you might consider even less reliable than ours.

Nothing designed by man is absolutely and perfectly failsafe. And major decisions about these doomsday devices are ultimately made not by all-knowing and infinitely wise philosopher-kings, but by elected politicians prone to miscalculation and misjudgment. According to recent and authoritative histories of the Cuban Missile Crisis, President John F. Kennedy balked at offering the Soviets a critical part of the bargain that ended the nuclear showdown, removing strategically useless American Pershing missiles from their bases in Turkey. His express motivation was that doing so publicly before the November 1962 elections would cost his party a dozen seats in Congress. Think about that for a moment.

There have been other times when the world stood at or approached the brink of total annihilation. Probably the closest call was during the 1983 NATO military exercise Able Archer, when there were elements within the Kremlin and the Red Army who were convinced that it was a cover for a preemptive nuclear strike against the Soviet Union ordered by their arch-enemy Ronald Reagan, and they seriously contemplated their own pre-emptive strike against the U.S.

In addition to the risks of political misjudgment, consider that the technology we rely upon is prone to mistakes, too. Here is a list of some of the occasions when Russian or American nuclear arsenals were put on high alert footing for imminent launch simply because of systematic errors: the 1979 "training tape incident," the 1980 "computer chip incident," the 1983 "autumn equinox incident," and the 1995 "Norway 'sounding rocket' incident." I don't believe that it is rational to trust our lives, and the continued existence of civilization, to the absolute reliability of computers, forever, without ever a technological glitch.

We know that people are bad at evaluating risks and calculating their consequences. Driving to the local airport is infinitely more dangerous statistically than taking a trans-oceanic flight, but many of us feel much more apprehension about the latter than we do about the former. And people are not very good at understanding remote but catastrophic dangers. The odds of a nuclear war today are practically nil. But over a sufficiently long time horizon, they become a probability.