As reported in the nytimes.com, "…97 percent of federal cases and 94 percent of state cases end in plea bargains," of which that percentage of criminal justice cases so resolved with a plea, thereby reflects that in virtually all cases the accused is never actually convicted by an impartial jury, and this plea so made is not done through a public trial or through a public forum, but is instead a situation in which the accused makes some sort of plea deal with the prosecuting arm of the State or of Federal auspices; coerced or not, fair or not, which effectively becomes the justice so rendered in those cases.
The Constitution of these United States, guarantees that in "…. criminal prosecutions the accused shall enjoy the right to a speedy and public trial, by an impartial jury," and is further entitled to "….due process of the law." In point of fact, there is absolutely nothing within the Constitution and the Amendments to such that address directly or indirectly the very concept of plea bargaining. Plea bargaining exists as a convenience as well as a tool for the State and for the Federal authorities; and it is effectively used as a shortcut to simply transact criminal cases in a manner of which suits those authorities, as well as allowing those authorities to exert an incredible amount of pressure on typically those that are not intimately familiar with criminal laws, the nuances of those laws, their Constitutional rights, as well as the fact that those so being accused of criminal actions, are often lacking both in the resources as well as the money to effectively fight back against those that are prosecuting them.
America has an almost endless list of criminal laws, of which, if the thinking is that each one of these laws are fair and equitable, and the corresponding punishment for such, appropriate; then it would behoove said country to actually go through the trouble of having public trials of all those so accused of those crimes, rather than circumventing such. Certainly, if this were to be done, the very first functional problem the United States would thereby encounter would be the overwhelming backlog of cases that would need to be brought to trial along with all the accouterments that go with trials and their outcomes, which would necessitate more of the taxpayer's money being devoted to prosecutorial elements, jailing, judges, courtrooms, and the like. Not to mention, that in order for anyone so accused to actually be convicted, necessitates juries of the people, consistently being willing to convict, again and again and again.
In actuality, though, if plea bargaining was no longer permitted, those currently being charged with various criminal offenses, would instead find, that after a relatively short period of time, that in lieu of the prosecution simply continuing to bully the poor, the oppressed, and the ill-educated till the end of time; that with so many cases being upon their plate, and with the plea bargain cudgel no longer being part of their perverted version of justice, that the criminal justice system would fundamentally changed from the current bastardization of justice that it presently so represents, to returning to that which would be of beneficence to the people, which would be to concentrate only on arresting those that have taken or interfered with one's life, liberty, or property, and nothing else.
Plea bargains are never going to be a fair part of any good criminal justice system; in fact, they are a reflection of a criminal justice system, gone horribly wrong and terribly amok.