Double Jeopardy is described as a rule of finality, the laudable purpose of which is to put to rest the effects of the first prosecution. It is expressed in the legal maxim "nemo debet bis vexari pro eadem causa" (no man shall be twice vexed for one and the same cause). 
The rule on double jeopardy has a settled meaning in Philippine jurisdiction, as provided in sec.21, Art.III of the Constitution of the Philippines which states that "[n]o person shall be twice put in jeopardy of punishment for the same offense." It only means that when a person is charged with an offense, and the case is terminated either by acquittal or conviction or in any other manner without the consent of the accused, the accused cannot again be charged with the same or identical offense.
Purpose of the Rule
The Rule against double jeopardy protects the accused not against the peril of the second punishment, but against the being again tried for the same offense. As held in the case of Julia vs Sotto (2 Phil 247), the Supreme Court explained that "[w]ithout the safeguard this article establishes in favor of the accused, his fortune, safety, and peace of mind would be entirely at the mercy of the complaining witness, who might repeat his accusation as often as dismissed by the Court and whenever he might see fit, subject to no other limitation of restriction than his own will and pleasure. The accused would never be free from the cruel and constant menace of the never ending charge, which the malice of the complaining witness might hold indefinitely suspended over his head, were it not that the judiciary is exclusively empowered to authorize, by an express order to that effect, the repetition of a complaint or information once dismissed in the cases in which the law requires that this be done. Such is, in our opinion, the fundamental reason of the article of the law to which we refer."
Double jeopardy is addressed exclusively to criminal offenses. It is a right which is available to avoid a second jeopardy involving the same offense. It must be noticed that the protection of the Constitutional inhibition is against a second jeopardy for the same offense, the only exception being, that "if an act is punished by a law and an ordinance, conviction or acquittal under either shall constitute a bar to another prosecution for the same act." The phrase same offense is construed to mean, not only that the second offense charged is exactly the same as the one alleged in the first information, but also that the first and second offense are identical. There is identity between the two offenses when the evidence to support a victim for one offense would be sufficient to warrant a conviction for the other. This is called the "same evidence test." Under the Rules of Court, there is identity between the two offenses, not only when the second offense is exactly the same as the first, but also when the second offense is an attempt to commit the first, or a frustration thereof, or when it necessarily includes in the offense charged in the first information. 
In order that the protection against double jeopardy may inure in favor of the accused, the following requisites must be present in the original prosecution: (a) valid complaint or information; (b) a competent court; (c) the defendant had pleaded to the charge; and (d) the defendant was acquitted, or convicted, or the case against him was dismissed or otherwise terminated without his express consent.
- ^ Yusingco vs. Ong (42 SCRA 589) 24 December 1971.
- ^ Melo vs. People. 85 Phil 766 (1960).
- Cruz, Isagani A. Constitutional Law. 2000 ed.
- People vs. Ylagan, 58 Phil 851 (1933).
- Cruz, et. al. vs. Enrile, GR 75983, 15 April 1988. En Banc. Narvasa, J.
- To learn more about the Philippine legal system, visit the Philippine Legal Database of Filipiniana.net Digital Library.