A recent opinion piece by public defender Jeffrey Stein does a nice job explaining why an innocent person would plea guilty:
You lay out options for your client. You could go to trial, but that might mean waiting in jail for months, if not years, before a jury hears the case. The idealist in you — the one who enrolled in law school to “change the system” and to fight for justice on behalf of those who need it most — hopes your client will proclaim a decision to go to trial. But a wary voice in the back of your head reminds you of the risk and life-altering consequences of losing.And Stein explains what, for many of us is a dreaded moment: when the judge asks if there is any reason why the court should not accept your client's offer to plea guilty:
You hesitate. You want to shout: “Yes, your honor! This plea is the product of an extortive system of devastating mandatory minimums and lopsided access to evidence. My client faced an impossible choice and is just trying to avoid losing his life to prison.” But you stand by your client’s decision, which was made based on experiences and emotions only they can know. You reply: “No, your honor.” The marshals lead your shackled client to a cage behind the courtroom. And the judge moves on to the next case.