"Those who would sacrifice essential liberties for a little temporary safety deserve neither liberty nor safety."
- Benjamin Franklin

I believe a good example of this is massive citizen surveilance. It'll give you a little temporary safety for as long as it takes the criminals to notice the surveilance cams. Shortly thereafter, criminals simply find ways around the surveilance cameras, and now criminals are still criminals, but honest citizens no longer have any privacy.

The same could be said for gun control. Outlawing guns will only give you some temporary safety as long it takes for the criminals to get guns illegally. So now criminals still have guns, but you, as a citizen, have lost a very essential liberty, and have also lost a massive amount of safety in losing the ability to protect yourself with weapons to match those of the criminals.