(Am I wrong to assume that you have not grown up in the US and have not attended school here?)
BBM: Because this is America and The US Constitution says we must .
(please forgive me if you do know all this and just don't want to accept it)
Everyone who attends school in the US, according to the curriculum, must take American History classes, learns about The Constitution, and what it stands for.
Even if a person confesses to the crime, he/she must go thru the rigmarole of the courts in some capacity .
If a defendant pleads "not guilty", they must be tried and convicted before they can be sentenced. The burden of showing guilt lies with the state; you are presumed innocent unless the state can prove your guilt beyond the shadow of a doubt- even if there is a video/witnesses of/to the crime A defendant need not actually believe that she is "not guilty" in order to enter this plea.
By pleading "not guilty" they are saying; "Guilt implies wrong-doing. I feel I have done no wrong. I may have violated some specific laws, but I am guilty of doing no wrong. I therefore plead not guilty." -this places the burden of proof on the state to prove guilt and bring the evidence to prove it; this insures that everyone gets a fair trial.
Roof would have pleaded "guilty" if the state would sentence him to LWOP (life without the possibility of parole), but the prosecutor (who represents The State) would not accept that plea from him.
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Some amendments to The Constitution insure that a person will get a fair trial:
Fourteenth Amendment to the United States Constitution
Amendment XIV
"Section 1.
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States;
nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws..."
https://www.law.cornell.edu/constitution/amendmentxiv
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Fifth Amendment to the United States Constitution
Amendment V
"No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb;
nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation..."
https://www.law.cornell.edu/wex/fifth_amendment
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Sixth Amendment to the United States Constitution
Amendment VI
"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the state and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and
to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the assistance of counsel for his defense..."
https://www.law.cornell.edu/constitution/sixth_amendment
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Here is some more info, if you are interested:
Proof, Burden of Proof, and Presumptions
"Proof, Burden of Proof, and Presumptions.In 1970, the Court held in In re Winship that the due process clauses of the Fifth and Fourteenth Amendments "[protect] the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged."1050 "The reasonable doubt standard plays a vital role in the American scheme of criminal procedure. It is a prime instrument for reducing the risk of convictions resting on factual error. The standard provides concrete substance for the presumption of innocencethat bedrock 'axiomatic and elementary' principle whose 'enforcement lies at the foundation of the administration of our criminal law."'1051 In many past cases, this standard was assumed to be the required one,1052 but because it was so widely accepted only recently has the Court had the opportunity to pronounce it guaranteed by due process.1053 The presumption of innocence is valuable in assuring defendants a fair trial,1054 and it operates to ensure that the jury considers the case solely on the evidence.1055..."
http://law.justia.com/constitution/us/amendment-14/59-burden-of-proof-and-presumptions.html
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Due Process of Law
"A fundamental, constitutional guarantee that all legal proceedings will be fair and that one will be given notice of the proceedings and an opportunity to be heard before the government acts to take away one's life, liberty, or property. Also, a constitutional guarantee that a law shall not be unreasonable, Arbitrary, or capricious.
The constitutional guarantee of due process of law, found in the Fifth and Fourteenth Amendments to the U.S. Constitution, prohibits all levels of government from arbitrarily or unfairly depriving individuals of their basic constitutional rights to life, liberty, and property. The due process clause of the Fifth Amendment, ratified in 1791, asserts that no person shall "be deprived of life, liberty, or property, without due process of law." This amendment restricts the powers of the federal government and applies only to actions by it. The Due Process Clause of the Fourteenth Amendment, ratified in 1868, declares,"[N]or shall any State deprive any person of life, liberty, or property, without due process of law" ...
Procedural Due Process
The phrase "procedural due process" refers to the aspects of the Due Process Clause that apply to the procedure of arresting and trying persons who have been accused of crimes and to any other government action that deprives an individual of life, liberty, or property. Procedural due process limits the exercise of power by the state and federal governments by requiring that they follow certain procedures in criminal and civil matters. In cases where an individual has claimed a violation of due process rights, courts must determine whether a citizen is being deprived of "life, liberty, or property," and what procedural protections are "due" to that individual.
The Bill of Rights contains provisions that are central to procedural due process. These protections give a person a number of rights and freedoms in criminal proceedings, including freedom from unreasonable searches and seizures; freedom from Double Jeopardy, or being tried more than once for the same crime; freedom from Self-Incrimination, or testifying against oneself; the right to a speedy and public trial by an impartial jury; the right to be told of the crime being charged; the right to cross-examine witnesses; the right to be represented by an attorney; freedom from Cruel and Unusual Punishment; and the right to demand that the state prove any charges Beyond a Reasonable Doubt..."
http://legal-dictionary.thefreedictionary.com/due+process+of+law
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The Burden of Proof in Criminal Trials
" The prosecution must not only produce evidence on every element of the crime, it must convince the trier of fact beyond a reasonable doubt..."
http://criminal.lawyers.com/criminal-law-basics/criminal-trials-who-has-the-burden-of-proof.html
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And last:
If a suspect confesses, why do they plead not guilty?
"...First thing to understand, said Bremerton defense attorney Tom Weaver, is the difference between innocent and not guilty.
Not guilty can mean innocent as people are presumed innocent until found guilty but in essence, pleading not guilty sets into motion the process where attorneys can review the case. Otherwise, once a plea is accepted, the next step is sentencing..."
http://pugetsoundblogs.com/kitsap-c...spect-confesses-why-do-they-plead-not-guilty/
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OK?....ok :facepalm:
Class has ended.