No attacks have occured in America since 9/11. Are we safer now than when our skyscrapers were falling in ruins? How do you measure?

It's an interesting question.
Is fear so strong that a wrongly spelled name in one e-mail or a luggage mistakenly (by an airport employee) sent to another destination than its owner, justify stopping a plane from taking off or from landing in the US, thus landing in Canada?
It's all in the nerves and it's mainly psychological!
The problem is: it could all be a diversion and they'll hit when we least expect it. Or it's crying wolf and very soon some might get exasperated.

Raoul