The Constitution does not guarantee the right of appeal against a criminal conviction.
Under federal statutes criminal defendants have right of appeal in federal court. As a matter of right, only one review is allowed to the US court of appeals. Review of federal or state convictions in the US Supreme Court is discretionary and not as a matter of right to the defendant.
In order to correct trial court errors, most states provide for the right to an appellate review of criminal sentences and convictions of state courts. Moreover,many states or jurisdictions confine the scope of such review to making of short oral arguments followed by decisions without explanation.
Wherever state law allows criminal appeal as a matter of right, the court is obliged to engage a court appointed attorney for the indigent defendant in appeal. For filing appellate review an indigent defendant is entitled to trial transcript free of charge.
In appeal the burden lies on the defendant to demonstrate that evidence was inadequate to warrant a conviction or sentence or that error occurred in the trial. In the very first appeal defendant must take all the grounds of trial error to preserve the same for further appeals, if any.
