The original trial court did not appoint a lawyer for Mr. Gideon because, according to Florida state law at the time, only defendants who had committed capital offenses and were indigent were entitled to appointed counsel. The U.S. Supreme Court held that the Sixth Amendment guarantees the right to counsel for all criminal defendants, regardless of the charged offense. This overturned the previous ruling in Betts v. Brady that only required counsel for capital cases. The Court agreed with Gideon that appointing counsel for indigent defendants is necessary to ensure a fair trial as required by the Due Process clause of the Fourteenth Amendment.