The truth about terrorism is that if you're willing to give up your life, as the truck driver in Nice was, there's not much anyone can do to stop you.

That's the nature of civilization. It depends people's basic goodness and their individual will to survive. If both those things go away all bets are off.

And the more advanced our civilization gets the more at-risk we are. If we didn't have trucks we couldn't be killed by trucks. If there were no jets they couldn't be crashed into skyscrapers. Etc. 

We have a lot of vulnerabilities that we simply can't safe-up. And we can't know who all the potential suicide drivers are. 

It's not a great idea to elect despots to solve the problem. You trade one problem for an even worse one. Although I'm sure they're thinking about exactly that in France, and we already know a fair number of Americans are thinking it too.