No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.
A defendant may plead guilty instead of insisting that the prosecution prove him guilty. Often the defendant does so as part of a
plea bargain with the prosecution, where the defendant is guaranteed a light sentence or is allowed to plead to a lesser offense. 1 Although the government may not structure its system so as to coerce a guilty plea, 2 a guilty plea that is entered voluntarily, knowingly, and understandingly, even to obtain an advantage, is sufficient to overcome constitutional objections. 3 However, some constitutional challenges may survive a plea if they go to "'the very power of the State' to prosecute the defendant."  4 The guilty plea and the often concomitant plea bargain are important and necessary components of the criminal justice system, 5 and it is permissible for a prosecutor during such plea bargains to require a defendant to forgo his right to a trial in return for escaping additional charges that are likely upon conviction to result in a more severe penalty. 6 But the prosecutor does deny due process if he penalizes the assertion of a right or privilege by the defendant by charging more severely or recommending a longer sentence. 7
In accepting a guilty plea, the court must inquire whether the defendant is pleading voluntarily, knowingly, and understandingly, 8 and
the adjudicative element inherent in accepting a plea of guilty must be attended by safeguards to insure the defendant what is reasonably due in the circumstances. Those circumstances will vary, but a constant factor is that, when a plea rests in any significant degree on a promise or agreement of the prosecutor, so that it can be said to be part of the inducement or consideration, such promise must be fulfilled. 9