The fault must be provided clearly.
Means that people do one. In that time, not guilty or legal provisions is wrong. But afterward, have enacted laws to punish the act shall be guilty cuisine. To make all persons to take any action. Because I'm afraid I have the law out later, and I'm afraid is wrong.
For example, to post information about damage to others or pornography, obscenity, on Facebook which posted on 9 June 2550 later was announced, the law. Act of computer on 10 June 2550 such action is not considered guilty. While do no law is wrong, but if done in the 10 June 2550. Such action constitutes a crime. Because the law is wrong.
It is the principle that "no law retroactive." but that any law To provide opportunities for the use of forced back. Do the conditions under which the important legal 2 folds.
1) must be clearly stated in the text of law that have?
2) enacted laws effective history. Whatever the case shall not apply retroactively by conflict with the provisions of the constitution.
Principle that "no law retroactive." the penal code section 2 paragraph first, said that "the laws that apply while the action act was wrong and the sentence. And the punishment to the offender. To blame the provisions of the law.