Having a less socially stigmatizing offense on one's record. Prosecutors may reduce charges that are perceived as socially offensive to less-offensive charges in exchange for a guilty plea. For example, a prosecutor may reduce a molestation or rape case to an assault. This can have a major impact on the defendant's relationship with friends and family. Perhaps even more critical, sometimes defendants convicted of stigmatizing offenses may be at a greater risk of being harmed (or killed) in prison than if they are convicted of an offense that doesn't carry the same stigma.
Avoiding hassles. Some people plead guilty -- especially to routine, minor first offenses -- without hiring a lawyer. If they waited to go to trial, they would have to find a good lawyer and spend both time and money preparing for trial.
Avoiding publicity. Famous people, ordinary people who depend on their reputation in the community to earn a living, and people who don't want to bring further embarrassment to their families all may chose to plead guilty or no contest to keep their names out of the public eye. While news of the plea itself may be public, the news is short-lived compared to news of a trial. And rarely is a defendant's background explored in the course of a plea bargain to the extent it may be done at trial.
Keeping others out of the case. Some defendants plead guilty to take the blame (sometimes called the "rap") for someone else, or to end the case quickly so that others who may be jointly responsible are not investigated.
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