My father, a public high school teacher in New Jersey for three decades, used to get really annoyed by Earth Day, a religious holiday that somehow gets an exemption from the First Amendment's Establishment Clause.
A born contrarian, Dad always used the occasion to give his students hard data showing that the sky isn't falling and that we're not all going to die. One Earth Day a couple of years before he retired, he was spreading the good news when a high school junior raised her hand to ask, "Mr. Healy, why are you so negative?"
Sometimes when I argue with conservatives about terrorism, I get a sense of how my father felt. Because when I tell my right-wing friends that al Qaeda isn't an "existential threat" to the United States — that we don't need to suspend our Constitution to keep ourselves safe — they tend to look at me like I'm some sort of communist.
Well, at the risk of sounding "negative," it's worth remembering that terrorism has always been a weapon of the weak — and it usually fails.
As the analysts at the Human Security Report Project explain, "the overwhelming majority of terrorist campaigns fail to achieve their strategic objectives." And, despite media sensationalism, fatalities from terrorism have actually declined by some 40 percent in recent years.
Terrorists bank on overreaction. As Osama bin Laden put it in 2004, "All that we have to do is to send two mujahedeen to the furthest point east to raise a piece of cloth on which is written al Qaeda, in order to make the generals race there to cause America to suffer human, economic, and political losses."
Adam Gadahn, the U.S.-born al Qaeda spokesman, recently called for more "lone-wolf" strikes, because "even apparently unsuccessful attacks on Western mass transportation systems can bring major cities to a halt [and] cost the enemy billions."
In the television show 24, Jack Bauer repeatedly battles terrorist masterminds with nuclear weapons. In real life, though, we're not facing TV-thriller supervillains.
When the enemy's best recent shot involves lighting his pants on fire, we shouldn't torture ourselves with nightmarish visions of weapons of mass destruction. Such weapons are exceedingly hard to come by.
As political scientist John Mueller notes in his recent book Atomic Obsession, "no state has ever given another state — even a close ally, much less a terrorist group — a nuclear weapon (or chemical, biological, or radiological one either)." And home-grown WMD tend to be ineffective.
The Japanese cult Aum Shinrikyo had roughly a billion dollars devoted to developing chemical and biological weapons, the most sophisticated such program in the history of terrorism. But when it released sarin gas on the Tokyo subway in 1995, it only managed to kill 12 people.
Building a nuclear weapon is even harder. Any group trying to do so faces "Herculean challenges," according to the Gilmore Commission, the advisory panel President Bush set up to assess terror threats in the wake of 9/11. There has been no known case, Mueller points out, of any appreciable amount of weapons-grade uranium disappearing.
None of this should be taken as a counsel of complacency. The low risk of terrorist WMD doesn't make guarding against it a waste of time. It makes sense, for example, to boost funding for international efforts to prevent nuclear smuggling, as the Obama administration has done. But when we overreact, we're doing terrorists' job for them.
Conservatives understand that exaggerated fears of environmental threats make government grow and liberty shrink. They'd do well to recognize that the same dynamic applies to homeland security.