Which punishment works best on the cruel and vicious?

In law school, the Intelligent Independent learned the theories of punishment: what we, as a society, hope to accomplish by punishing people for crimes. I remembered the list with a handy little acronym I made up: "Criminals are DIRRD"

• Deterrence, both specific (deterring the criminal from future crimes) and general (deterring society from criminal behavior)
  
• Incapacitation (while they're locked up, they can't hurt anyone else)
  
• Rehabilitation (might as well try to fix them while we've got 'em)
• Retribution (Biblical punishment -- Old Testament style)
  
• Denunciation (think Scarlett Letter -- most people don't want to be thought of as a criminal)

All five of those apply to the members of a high school cheer-leading squad who lured a girl to someone's house and then beat her senseless for a half hour while the video camera rolled.

The Intelligent Independent's position? Try these animals as adults.

We have no mercy for the cruel and the vicious. They'll likely get probation and lots of community service -- maybe a few days in jail. The Intelligent Independent would give them all jail time, and lock up the ringleaders until their 21st birthday.