I'm sorry but that particular commandment conforms with kant's 2nd formulation of the categorical imperative and should be stated as 'thou shall not KILL'.
First, the categorical imperative is defined as an action that accrues to no other good but itself. If capital punishment is indeed moral, then, the command not to kill becomes only a subjective imperative, one that accrues to a higher good -- which contradicts the categorical imperative itself.
Second, the right to life is an INALIENABLE right. Such a right is INDEPENDENT OF POSITIVE LAW. If the commandment is indeed about murder, then some forms of killing, that which is sanctioned by the state, becomes permissible, hence contradicting the nature of inalienable rights.
An inalienable right is one that does not comes from men. It would thus have to appeal to a God or to a moral order.
The declaration of Independence says that all men are endowed by their creator with certain rights among them being life, liberty, and the pursuit of happiness. In short, no man has the authority to take away what God has given.
Which goes back to what I was saying. God cannot be guilty of breaking a law when He
is the authority upon which it is based. God has a right to take away your physical life as He has done to 100% of the worlds past population so far.
But God can also give men authority to take life under some circumstances - a just war, just capital punishment, and self-defense are three examples. And all three are upheld by our courts as valid and not opposed to the spirit of the Declaration of Independence and all three are approved of in the bible and not considered to be a violation of the commandment not to kill. Our legal system does mirror the bible to a great degree.
If that commandment is indeed about murder, and not just killing, then states derive the ability to make exceptions by the same authority that man claims the right to begin with. If the commandment is about just killing then the bible contradicts itself when it commands killing and the state which actually does base current law on the bible (though some would not like to believe that) must appeal to a moral order or to an unnamed God and not to the God of the bible. Which God or order do YOU think the Founding Fathers appealed to?
They appealed to John Lock of course, and he said:
"The state of nature has a law of nature to govern it,
which obliges every one: and reason, which is that law,
teaches all mankind, who will but consult it, that being
equal and independent, no one ought to harm another
in his life, health, liberty, or possessions:
for men being all the workmanship of one omnipotent,
and infinitely wise maker; all the servants of one
sovereign master, sent into the world by his order,
and about his business; they are his property,
whose workmanship they are, made to last
during his, not one another’s pleasure...
Every one...may not, unless it be to do justice
on an offender, take away, or impair the life,
or what tends to the preservation of the life, the liberty,
health, limb, or goods of another.
God hath certainly appointed government to restrain
the partiality and violence of men."
http://www.avantrex.com/essay/freetalk.html
In other words Locke is saying that men ought not to be harmed because they are the property of God. Which squares with the bible when it talks about the time David committed adultery and then murdered a man. David responds and says: "I have sinned against the Lord." earlier when Joseph is asked to commit adultery he answers: "How then could I do such a wicked thing and sin against God?"
Both man's law and Man's inalienable rights derive it's authority from God and the necessity to not sin against God.
Many are trying to change that, but so far the history of the world shows us that the results are far more detrimental then the results of recognizing God's sovereignty.
