[red-beard]

I present the 5th and 6th Amendments:

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.

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://en.wikipedia.org/wiki/Presumption_of_innocence

In many states, presumption of innocence is a legal right of the accused in a criminal trial, and it is an international human right under the UN's Universal Declaration of Human Rights, Article 11. Under the presumption of innocence, the legal burden of proof is thus on the prosecution, which must collect and present compelling evidence to the trier of fact. The trier of fact (a judge or a jury) is thus restrained and ordered by law to consider only actual evidence and testimony presented in court. The prosecution must, in most cases prove that the accused is guilty beyond reasonable doubt. If reasonable doubt remains, the accused must be acquitted.

So, that is why.