What was the last U.S. state to accept the idea that every person is presumed innocent (the presumption of innocence) until proved guilty in court?

Although the Constitution of the United States does not cite it explicitly, presumption of innocence is held to follow from the 5th, 6th, and 14th amendments. The case of Coffin v. United States (1895) established the presumption of innocence of persons accused of crimes. Also note In re Winship. In 1974, the Louisiana Constitution added the presumption of innocence to the right to a fair trial. The last state to do so.

Within American jurisprudence and the legal system, the presumption that a person is innocent of committing a crime until he or she has been proven guilty is totally fundamental. For a very long time, this presumption worked in all the states with the exception of Louisiana. The legal system in Louisiana was not founded on the British common law tradition which was used everywhere else. Instead, Louisiana used the Napoleonic Code. The rest of America had a legal tradition that had key roots in ancient Roman law.

Due to the presumption of innocence, a person cannot be compelled to confess guilt or give evidence against him/herself. It is for the state to produce evidence of guilt, not for the defendant to prove innocence. So this is not just an ideal; it is an actual legal presumption in law.

The legal scholar James Bradley Thayer (1831 - 1902) summed it up: "The presumption of innocence reflects a long-standing societal judgment that ‘in the eyes of the law every man is honest and innocent unless it be proved legally to the contrary.”