There's this Fifth Amendment to the constitution basically saying you cannot be forced to give up incriminating evidence. You don't have to answer any questions about a crime you are suspected of committing. The tricky part is when does coercion start? What if you say something and it is taken out of context? "If I felt the need to kill him, I would tell you 'I killed him.'" Well, in this case the suspect did say the words "I killed him." Can anything you say be used against you in a court of law? According to Miranda vs Arizona, as long as you are informed that you do not have to talk without an attorney present, your testimony is admissible. If we, as a nation find different, the law will change.
I believe there are cases where people end up confessing to a crime after being questioned endlessly about it. I think all people should receive legal counsel before being asked questions, so they understand that they could possibly perjure themselves. Beyond that, I do not believe a confessions should be retracted.
No, those accused of a crime should not be allowed to retract a confession, because confessions are very powerful tools in solving crimes. As long as the confession was not made under coercion, there is no reason not to allow it to stand. Confessions are a good way to hold someone accountable for their crimes.
In my opinion, a confession is an admission of guilt and once it has been uttered, it should stand. Retraction of a confession should absolutely not be allowed unless it can be proved that the accused was severely coerced into making the confession. We have made it too easy for criminals to retract statements and plea bargain. A criminal commits an illegal act and knows at the get go that he or she will never serve a full sentence for it.
If you give a confession, and accept guilt for the particular crime that you are in custody for, then you should not be able to retract it. Once someone says they did the act of crime, they should be found guilty and then face a judge to see what their sentence is.