I’m no security expert. But Bruce Schneier is a leading scholar in the field, and in this interview he makes some of the same points as I did here and here:
Air travel survived decades of terrorism, including attacks which resulted in the deaths of everyone on the plane. It survived 9/11. It’ll survive the next successful attack. The only real worry is that we’ll scare ourselves into making air travel so onerous that we won’t fly anymore. We won’t be any safer — more people will die in car crashes resulting from the increase in automobile travel, and terrorists will simply switch to one of the millions of other targets — and we won’t even feel any safer. It’s frustrating; terrorism is rare and largely ineffectual, yet we regularly magnify the effects of both their successes and failures by terrorizing ourselves. [emphasis added]….
Politicians naturally want to do something in response to crisis, even if that something doesn’t make any sense. But unfortunately for politicians, the security measures that work are largely invisible. Such measures include enhancing the intelligence-gathering abilities of the secret services, hiring cultural experts and Arabic translators, building bridges with Islamic communities both nationally and internationally, funding police capabilities — both investigative arms to prevent terrorist attacks, and emergency communications systems for after attacks occur — and arresting terrorist plotters without media fanfare. They do not include expansive new police or spying laws, or security theater measures that directly target the most recent tactic or target. …
Of course 100% security is impossible; it has always been impossible and always will be. We’ll never get the murder, burglary, or terrorism rate down to zero; 42,000 people will die each year in car crashes in the U.S. for the foreseeable future; life itself will always include risk.
I don’t agree with all of Schneier’s claims. For example, terrorists often do succeed in achieving their political objectives as Robert Pape shows in this article, which is one of the main reasons why terrorism persists. But his arguments (even the ones I have reservations about) are well worth considering.