Of course, it is hard to horrify a multitude which views slaughter every night on TV or engages in it via video games. Without that, the deterrent falls victim to desensitization.
In the '50s, just the idea of a visit to ol' Sparky, or the gas chamber was enough to get many thinking. Not so any more.
Now a death sentence mostly means spending the rest of your life nice and safe in court until you die of old age.