"A plea of guilty differs in purpose and effect from a mere admission or an extrajudicial confession; it is itself a conviction. Like a verdict of a jury it is conclusive. More is not required; the court has nothing to do but give judgment and sentence."

"Out of just consideration for persons accused of crime, courts are careful that a plea of guilty shall not be accepted unless made voluntarily after proper advice and with full understanding of the consequences."

A plea of guilty is more than a confession which admits that the accused did various acts; it is itself a conviction; nothing remains but to give judgment and determine punishment.

"The court in exercise of its discretion will permit one accused to substitute a plea of not guilty and have a trial if for any reason the granting of the privilege seems fair and just."

In the subsequent trial, the court allowed the prosecution to introduce the defendant's withdrawn guilty plea as evidence of guilt.

And long before Shepard, the Court stated that a guilty plea "is itself a conviction" and that "[l] ike a verdict of a jury it is conclusive."

—on timely application, the court will vacate a plea of guilty shown to have been unfairly obtained or given through ignorance, fear or inadvertence

The standard for determining the validity of a guilty plea remains whether it "represents a voluntary and intelligent choice among the alternative courses of action open to the defendant."