Ne bis in idem (Latin: "not twice for the same thing") is the principle that no one may be prosecuted or punished again for an offence of which they have already been finally acquitted or convicted. In common law systems it is known as the rule against double jeopardy.
Purpose
The principle protects individuals from the oppression of repeated prosecutions by the state, which has far greater resources, and it protects the authority of final judgments. It also reflects fairness: once the state has had its opportunity to prove guilt, the matter should be closed.
International Recognition
Article 14(7) of the International Covenant on Civil and Political Rights provides that no one shall be liable to be tried or punished again for an offence for which they have already been finally convicted or acquitted in accordance with the law and penal procedure of each country.
In Indonesia
The Indonesian Criminal Code bars a second prosecution for the same act that has been decided by a final judgment of an Indonesian court. The principle also has a civil law counterpart: under Article 1917 of the Civil Code, a claim already finally decided between the same parties, on the same object and grounds, will be declared ne bis in idem.
Exceptions
Some jurisdictions permit a retrial in narrow circumstances. In England and Wales, Part 10 of the Criminal Justice Act 2003 allows the Court of Appeal to quash an acquittal for certain serious offences where there is new and compelling evidence. A retrial may also follow a successful appeal against conviction, which is not regarded as double jeopardy.