Abstract:
The objective of this thesis is to study that the retroactive principle is the general principle of law, which can apply to all types of laws including laws having non-criminal penalty. Based on Article 39 of the Constitution of the Kingdom of Thailand B.E. 2550, which stipulates that No person shall be inflicted with a criminal punishment unless he has committed an act which the law in force at the time of commission provides to be an offence and imposes a punishment.., there is an interpretation that the retroactive principle can only apply to the laws having criminal penalty, and cannot apply to the laws having non-criminal penalty. In considering that the retroactive principle can apply to what types of law, it needs to consider the significance of this principle that, its objective is for guaranteeing the protection of peoples rights and liberties, which are fundamental rights written in the Constitution to endorse that, in the future, there will be no new law enacted to have retroactive impacts to any action which had occurred and completed before such law was promulgated. Furthermore, Thailand is a country being governed by democratic system, and having its administration under the rule of law, thus, considered as a legal state. If the country does not respect the retroactive principle, people will not have any security in their activities done in the past, and any certainty in those to be done in the future, alike. If the retroactive impacts of the new laws are allowed, the rights and liberties of people would be fragile, since the guarantee of them is missing. For this reason, civilized countries do not limit the use of retroactive principle to be narrow only for the laws having criminal penalty, but do apply this principle for other laws having non-criminal penalty as well. For the adjudications and judgments in all cases to be done with justice, and, for the protection of peoples fundamental rights to be enabled, it is proposed that, the provision in the Constitution of Thailand should be amended by having the retroactive principle to broadly apply for all types of laws.