President Obama today used his executive authority to commute the prison term of Ceasar Cantu, a convict who otherwise would have spent an extra three and a half years behind bars thanks to a typo. In 2006, Cantu pleaded guilty to conspiracy to possess with intent to distribute marijuana and money laundering. His plea agreement with prosecutors resulted in Cantu falling under a base offense level of 34, meaning he'd spend roughly 11 and a half years in jail.

But in his pre-sentence report, that "34" number was mistakenly replaced with a 36 — tacking an extra 42 months onto Cantu's prison stay. As a result, he was sentenced to 15 years. And it gets worse: by the time the error was caught, Cantu and his lawyers were told that it was too late to correct the mistake through any judicial process. Their only hope was President Obama, who has exercised his clemency powers sparingly while in office.

Obama saw fit to step in here, however, by cutting Cantu's sentence back down to the original 138 months. "Given the circumstances of this case and the manifest injustice of keeping a person in federal prison for an extra three and a half years because of a typographical mistake, the president wanted to act as quickly as possible," said White House press secretary Jay Carney. "This is a matter of basic fairness and it reflects the important role of clemency as a fail-safe in our judicial system."