Philip Holloway, a CNN legal analyst, is a criminal defense lawyer who heads his own firm in Cobb County, Georgia. A former prosecutor and adjunct professor of criminal justice, he is former president of the Cobb County Bar Association's criminal law section. Follow him on Twitter: @PhilHollowayEsq The opinions expressed in this commentary are solely those of the author.

(CNN) How young is "old enough" to be an adult criminal?

An 11-year-old boy in Tennessee is facing first-degree murder charges in the death of an 8-year-old he shot after he asked to see her puppy and she said no. The boy used his father's 12-gauge shotgun, taking it from an unlocked closet, according to a story in the Washington Post. The local prosecutor will decide whether to charge the boy as an adult.

Nobody with a soul can seriously ignore the tragic nature of the death of any child. However, two wrongs do not make a right; prosecuting a very young child for murder and sending him to prison for life is tragic in and of itself. It essentially takes the life of another child and causes unimaginable heartache for others.

For centuries American and English common law held that children under age 14 were not legally capable of forming criminal intent. For any crime to occur, there must be the convergence of what is known as the "actus reus" (the guilty act) and the "mens rea" (the guilty mind, also known as criminal intent).

Without these two necessary pieces, a crime does not exist. State legislatures across America have largely changed the traditional common-law idea that children are unable to formulate criminal intent. There is no national standard in determining at what age a child can be treated as an adult in the criminal justice system. The result is that approximately 200,000 American children are charged and incarcerated every year -- as adults, according to the Open Society Foundations.

Fourteen states have no minimum age at which children can be prosecuted as adults, according to the Equal Justice Initiative. In some cases children younger than 10 have been prosecuted as adults.

I suggest that except for extraordinary circumstances, no child under the age of at least 17 should be sentenced to lengthy incarceration in adult jails. It is beyond debate that the human brain does not reach anything close to maturity until the early to mid 20s.

Therefore it stands to reason that an adolescent or prepubescent child cannot understand the nature and the consequences of their actions. Why, therefore, in a rational society would anyone think it is appropriate to apply adult consequences to the choices made by children?

The answer? Emotional knee-jerk reactions by politicians who pass laws without considering the bigger picture.

For example consider the case of little Amy Yates, age 8 at the time she died, strangled in Georgia in 2004.

At the time it was widely believed that her 12-year-old neighbor Jonathan Adams was guilty of the crime. According to Georgia law at the time the maximum penalty Adams could face was two years in confinement due to his age. He entered a plea without admitting guilt but it is now widely believed he was in fact innocent.

Nevertheless, the Georgia Legislature responded almost immediately and unanimously out of emotion and passed what is known as "Amy's Law" which would have provided for five years incarceration.

Every state in the United States has some procedure in place to prosecute children as adults under certain circumstances.

And there can be no doubt that sometimes it is appropriate to do so -- especially in cases where the offender is somewhat older and it can be shown that person is not capable of rehabilitation and where there is strong evidence of planning. Sometimes there may be evidence the person knew and understood the nature and consequences of their actions, which could justify an adult prosecution

But the fact remains that children are children -- they are not adults and their brains do not work the same as an adult. Just ask any parent. Children cannot enlist in the military. Children -- indeed, adults under 21, cannot legally order a beer. Children cannot enter into contracts. Children cannot make legal decisions for themselves, but they CAN be held to adult standards if they are charged with crimes.

And almost beyond belief, children can be executed for crimes they commit at very young ages.

Setting aside for the moment that the punishment may sometimes fit the crime, it is worth noting that children in adult prisons do you not fare well at all. Approximately 10,000 children are held in adult jails and prisons in the United States.

These are kids who are five times more likely to be raped or otherwise sexually assaulted than in juvenile facilities. The risk of suicide is likewise much higher for juveniles in adult jails. This raises the issue of whether prolonged incarceration of children violates the Eighth Amendment's prohibition against cruel and unusual punishment.

There is little if any evidence to suggest that treating juveniles as adults in the criminal justice system decreases crime or has any deterrent effect. In fact, what evidence does exist suggests the opposite. Studies show that incarcerating children more often than not results in higher rates of recidivism; essentially, it turns children into hardened criminals.

But I don't need studies to tell me this because I have seen it for myself.

I have worked in and around the criminal justice system for about 28 years. I was trained to believe that juvenile courts were courts of rehabilitation rather than punishment. I was trained to believe that children were salvageable whereas sometimes adults are not.

I still believe that to be the case, but in my lifetime there has been a drastic shift from notions of rehabilitation to quests for revenge and vengeance regardless of the age of the accused.

As a parent I know without question that children do not think about the world around them the way we adults do. They have little if any perspective and they often use poor judgment.

It may not be possible to come up with a bright line rule defining the age at which a child can be tried as an adult. It should depend on a case-by-case analysis based on the child's age and other relevant factors. This decision should be left to judges with the help of psychiatrists and psychologists rather than ad-hoc legislative determinations. After all, that's why we have judges -- to make decisions based on the totality of the circumstances.