Laws evolve over time. It is important because time changes so much in the world. Different times call for different measures. Lawmakers learn from experience, too, and make legislative changes as a result of finding rules or processes that don't work.
Because laws change over time, a person who is charged with a crime today might be handled differently than a man charged with that crime ten years ago. A Colorado sex crime defendant is an example of how laws change and how timing can make a big difference in a person's ability to avoid criminal conviction.
The "corpus delicti" rule made it so prosecutors in a criminal case had to have more evidence that a crime was committed than a suspect's confession in order to convict him of a crime. When the law was put in place at least a hundred years ago, its purpose was to prevent people from going to prison without sufficient evidence. False confessions happen, sometimes as a result of unethical interrogation techniques. Requiring further evidence was a way to try to ensure that innocent people weren't wrongly punished.
On Monday, the Colorado Supreme Court put an end to corpus delicti. Now, a suspect's "trustworthy and reliable" confession is enough evidence to lead to a criminal conviction. If this had been the law when a father was charged with the sexual assault of a child and incest, he would have been convicted and likely imprisoned.
The man was charged with the sex crimes when a confession wasn't enough for a conviction. A trial court convicted him of the abuse; that conviction was later overturned by a court of appeals due to corpus delicti. A lack of other evidence meant that convicting the defendant based on his verbal confession alone wasn't an option at the time.
The state Supreme Court's recent decision to change the law still won't affect the outcome of the defendant's case. A retroactive application of the change would put so many past criminal cases in states of flux and potentially innocent people at the center of a criminal investigation that they thought was over with years ago.
Source: The Denver Post, "Colorado high court changes rules for confessions, proof of crime not needed," Jessica Fender, Jan. 14, 2013