Why is the Gideon decision regarded as a historic civil liberties victory

The Gideon v. Wainwright decision is regarded as a historic civil liberties victory because it guaranteed for the first time in the history of the United States the assistance of a lawyer in all criminal cases.

Explanation:

In the famous case Gideon v. Wainwright, of March 18, 1963, the Supreme Court ruled that States were required, by mandate of the Fourteenth Amendment of the Constitution, to provide legal assistance in criminal matters to all persons, and not only to those who faced cases of capital punishment, who lacked resources to pay their defense. In this way, it overruled expressly what it had decided earlier in the case Betts v. Brady, June 1, 1942, where it argued that, unless certain personal circumstances in the defendant concurred, such as illiteracy or mental disability, or it was a particularly complicated case, it was not necessary the assistance of a lawyer ex officio in the criminal proceedings of state courts.

According to Oyez, "The Sixth Amendment's guarantee of a right to assistance of counsel applies to criminal defendants in state court by way of the Fourteenth Amendment."

So, this is a major victory as it protects criminal defendants in a whole new court of law.