4 theories
http://en.wikipedia.org/wiki/Jurisprudence
Answers to these questions come from four primary schools of thought in general jurisprudence: [2]
Also of note is the work of the contemporary Philosopher of Law Ronald Dworkin who has advocated a constructivist theory of jurisprudence that can be characterized as a middle path between natural law theories and positivist theories of general jurisprudence. [5]
"Howard Marsellus, a former chairman of the Louisiana pardon board, admits that \nhe was responding to political pressure when he voted, in 1984, to execute \nTimothy Baldwin, a man he believed was innocent of the bludgeoning death of an \neighty-five-year-old woman. "I'm guilty as sin," Marsellus says. "I did \nsomething morally wrong. I gave in to the prestige and power, the things that \nwent with my job. I knew what the governor, the man who appointed me, wanted: no \nrecommendation for clemency in any death case." Marsellus says he is haunted by \nBaldwin's execution. "The man walked in [to the execution chamber], grabbed the \nmicrophone, and looked dead in my face and said, 'Y'all are about to execute an \ninnocent man and someday you'll have to answer for this.' Man, I will carry this \nto my grave.""
http://www.theatlantic.com/past/issues/99nov/9911wrongman.htm
The Atalantic, November 1999, The Wrong Man by Alan Berlow
It is better to risk saving a guilty person
than to condemn an innocent one.
--Voltaire
http://www.theatlantic.com/past/issues/99nov/9911wrongman2.htm
Just how often the police actually get the wrong man is nothing short of astounding. A 1996 Justice Department report, Convicted by Juries, Exonerated by Science: Case Studies in the Use of DNA Evidence to Establish Innocence After Trial, found that in 8,048 rape and rape-and-murder cases referred to the FBI crime lab from 1988 to mid-1995, a staggering 2,012 of the primary suspects were exonerated owing to DNA evidence alone. Had DNA analysis not been available (as it was not a decade earlier), several hundred of the 2,012 would probably have been tried, convicted, and sentenced for crimes they didn't commit.