If a defendant, opts not to go to trial, he can either plead guilty or nolo contendre. A nolo contendre plea is also called a plea of "no contest." With a guilty plea, a defendant admits that he committed the offenses to which he is pleading guilty. With a nolo contendre plea, the defendant does not admit to the conduct forming the basis of the offenses to which he is pleading no contest. Rather, he acknowledges that if he went to trial, the Commonwealth would have sufficient evidence to prove that he committed the offenses, assuming that the finder of fact (a judge or jury) believed this evidence. When it comes to sentencing and post-sentencing rights, pleas of guilty and nolo contendre have the exact same effect.
In most cases resolved without a trial, a defendant pleads guilty to some of the charges, while other charges are dropped pursuant to a plea agreement. In some counties, it is also customary for the Commonwealth and Defense to reach an agreement concerning sentencing as well. The obvious question is under what circumstances a defendant would plead nolo contendre rather than entering a guilty plea. The classic nolo contendre scenario is where a defendant was so highly intoxicated, that he has no recollection of committing the crime. At the same time, the defendant does not dispute that he engaged in criminal conduct. He is aware that he was in a black-out state of intoxication and he is aware of witness statements and physical evidence against him. In such a scenario, the defendant cannot plead guilty, because he cannot admit to something he has no recollection of doing.
Another nolo contendre scenario involves a situation where a defendant does not want to admit to the alleged criminal conduct, but he also does not want to risk going to trial. Usually, plea offers contemplate a much more favorable outcome for a defendant than what he could expect if he loses at trial. Thus, a defendant may have a logical incentive to wish to avail himself of a plea agreement, even if he cannot admit to the conduct. Obviously, in some cases, the defendant is factually guilty, but just will not admit it. In other cases, the defendant is factually innocent, but still does not want to risk a trial.
Sometimes, prosecutors insist that a defendant plead guilty rather than nolo contendre, as a condition of the plea agreement. This is has more to do with principal than any valid legal rationale. In other cases, the prosecutor just wants the case to go away without a trial. For example, in any case with a child victim, a prosecutor will normally accept a nolo contendre plea if it means sparing the victim from testifying at trial.
Matt McClenahen is a criminal defense attorney in State College, Pennsylvania, home of Penn State University. He limits his practice to criminal law matters. http://www.mattmlaw.com/Criminal-Defense-Overview/