So the government takes the wrong approach to voting-machine security. What about airport security and its role in preventing terrorism? Bruce Schneier is not much more encouraging on that front than he was on the voting machines:

Bruce Schneier: The mistake is the focus. Counterterrorism in the United States is very much a political issue. It's important as a politician to defend against what the bad guys did last week, because you're going to look really bad if they do it again. So you're forced, really by politics, to spend more money defending against particular tactics than you are defending against the broad threat. And the TSA is the artifact of that.

The terrorists used airlines in 2001 in a particular way, and we need to make sure they never do that particular thing again. So what we get is an institution focused on defending against tactics rather than the threat. And like any institution, once it's formed, once it's brought into existence, it has to continue to justify its own existence. So you get an ever-increasing amount of airline security at the expense of general security.

Remember, every dollar spent taking away liquids is a dollar not being spent on Arabic translators. And taking away liquids only works if you're lucky enough to guess the plot correctly. Arabic translators work regardless of what the plot is.

Know It All: You recently demonstrated an ability to get liquids past security in any case. But you do say there has been some progress in securing air travel.

Schneier: I've said there are two things - reinforcing the cockpit doors, and convincing passengers they have to fight back. Everything else has been a red herring. People have argued with me that sky marshals also have been effective, but sky marshals are interesting - it's not the sky marshals that are effective, it's the idea of sky marshals that is effective. If you convince the public that you have sky marshals, you don't actually need them.

Schneier:Government is just big, and I think big is bad at this. If it's a massive company like an airline or an automobile manufacturer, they have the same problems with overrun systems -- the difference is, they're more likely to pull the plug quicker. Because they have a financial bottom line to worry about every year, every quarter, whereas a government is more likely to have an entrenched bureaucracy.

Schneier: You should learn that if you don't get the economics right, no security will work. A lot of these failures aren't technical failures, they're motivational failures, they're tradeoff failures, they're failures in the economics that make the system work. You should take away from this that security is hard, that it's not a matter of tossing a piece of technology at a problem, and suddenly it works. The devil is in the details, and the details are complicated.