Two words: Capital punishment.
No mercy for the merciless.
How many senseless, brutal, horrible murders happen in the USA each and every year?
In 2012 in all the USA, 43 people were executed for committing capital crimes. That is about 3-1/2 people per month or fewer than 1 per week. The average number of years on death row from the time they are convicted until they are executed - just over 10 years. One guy in 2012 had been on death row for 26 years.
There were more than 14,700 murders in the USA in the last posted statistics I could find. A fairly small percentage of the murderers are convicted but I didn't take time to locate a verifiable number.
Chicago alone averages more than 40 murders every month - from 2001 to present, more than twice as many Americans have been murdered in Chicago than have died from all causes in Afghanistan during that same period.
So looking at statistics like that, it is pretty easy to see that most people who commit murders and other senseless crime feel like the odds are pretty good that a) they won't be caught and b) if they are caught they won't be convicted and c) if they are convicted, they won't have to spend all that much time in prison and the odds against them ever being executed are great. Most especially the young feel pretty invincible.
We need a return to conscience, responsibility, accountability, and reverence/respect for the lives and rights of others. Obviously the legal system isn't accomplishing much in the way of deterrance.