Draconian punishments (Re: Correct me if I'm wrong...)
Yes, some states do use draconian punishments. For starters, there is thing that some states have called "the death penalty", which is especially troubling given the notoriously high false-postive conviction rate, especially for poor blacks. There are also many individuals serving life in California for committing three minor offences (such as stealing toilet roll etc, for which charges might have been upgraded above what the evidence supports in order to fall into the scope of the "three-strikes" legislation).
And when it comes to illustrations of the injustice of plea bargaining, there are cases such as the one involving the environmental activist Daniel McGowan, where federal and state prosecutors obtained a seven year sentence and a $1.9M fine for arson. This would almost certainly have been life if he had not changed his plea to guilty for some charges. And even with the guilty plea, it could still have been 30 years if the prosecutors had been succesful in having it reclassifying it as an terrorist offence. Contrast this with his "co-conspirators" facing exactly the same charges for exactly the same offences; by agreeing to plead guilty to a shoppling list of offences, and agreeing to testify against others named by the prosecutors, they were effectively let off with no material punishment.
The extreme consequences of refusing to agree to full cooperative plea bargaining can seem to make a mockery of the notion of justice, and end up looking like a form of forced confession. In the Daniel McGowan case, arguments have been made that plea-bargaining was used as a tool to rout out political dissidents, and dissent, rather than achieving justice. (Which seems to be supported by findings that police maliciously tortured fellow activists.)
Arguably, similar things happen in the UK, even at the lowest level (e.g. contesting an erronous fixed penalty notice carries a high risk of ending up with punative fines, legal costs, and a criminal record, especially when many magistrates are perhaps a bit too ready to accept the word of a police officer). It is worrying that the UK government seems keen to extend the use of plea bargaining.
As for Aaron Schwarz, he had been told he would face six months even if he pleaded guilty to every single charge the prosecutors decided to add to the list. And he would still face a hefty legal bill that he could not afford. Put yourself in his position, would you be happy to go to prison for six months, and plead guilty to things you think you had not done, and be branded as a convicted criminal for the rest of your life, or would you fight, but risk the technical possibility of 35+ years in prison? And this for someone who suffered from depression.