Kant offered a libertarian account of punishment-where he argued that we can be free internally (In our minds) to follow the moral law, and externally (Politically) by being able to pursue our own ends. According to Kant crimes such as Theft, and Murder are wrong as they are not universalizable, and bring us back to a state of nature-(A system where there is no laws).
Therefore in response to this, society must reverse the maxim on the criminal. This means that the thief should have his property taken, and the murderer should be killed. Therefore Kant’s maxim becomes “Whatever underserved evil you bring upon another person, should be brought on yourself”
Kant therefore believes that the punishment for crimes, should be retribution.