A plea bargain is what is typically used to resolve a criminal case. Not all cases head to the court for a determination there. With a plea bargain, you agree to plead guilty, but in return, you typically get a lesser charge than if you were to stand trial for the crime. It's also possible to have related charges dismissed in some cases.
Plea bargains, in general, are usually encouraged by the U.S. court system, because it reduces the burden on the criminal court calendars and sometimes reduces the number of people entering jails or prisons. This means that it's much more likely that you'll be able to arrange a plea than not. This works well for anyone who has to plead guilty due to solid evidence, as well.
There are a number of kinds of plea bargains that might be made. For instance, if you're charged with an assault or battery charge, you may be able to plea for something like disorderly conduct, a lesser charge, or to remove a count of the charge. You may also be able to exchange a guilty plea for a less severe sentence if the evidence is stacked against you. You always have the option to go to trial, but a plea allows you to know what you'll have to do in the future ahead of time.
A plea bargain gives you options you may not have otherwise, but clearly, if you aren't guilty of the crime, you could be pleading guilty to something you didn't do. If you have questions about plea bargains or how to defend yourself against charges, speak with someone who understands your rights and the way a criminal court system works.
Source: FindLaw, "Plea Bargain Basics" Oct. 15, 2014