A paramount principle of the law of extradition provides that a State may not surrender any individual for any offense not included in a treaty of extradition. This principle arises from the reality of extradition as a derogation of sovereignty. Extradition is an intrusion into the territorial integrity of the host State and a delimitation of the sovereign power of the State within its own territory. 1 The act of extraditing amounts to a "delivery by the State of a person accused or convicted of a crime, to another State within whose territorial jurisdiction, actual or constructive, it was committed and which asks for his surrender with a view to execute justice

A paramount principle of the law of extradition provides that a State may not surrender any individual for any offense not included in a treaty of extradition. This principle arises from the reality of extradition as a derogation of sovereignty. Extradition is an intrusion into the territorial integrity of the host State and a delimitation of the sovereign power of the State within its own territory. 1 The act of extraditing amounts to a "delivery by the State of a person accused or convicted of a crime, to another State within whose territorial jurisdiction, actual or constructive, it was committed and which asks for his surrender with a view to execute justice." 2 As it is an act of "surrender" of an individual found in a sovereign State to another State which demands his surrender 3 , an act of extradition, even with a treaty rendered executory upon ratification by appropriate authorities, does not imposed an obligation to extradite on the requested State until the latter has made its own determination of the validity of the requesting State's demand, in accordance with the requested State's own interests.

The principles of international law recognize no right of extradition apart from that arising from treaty. 4 Pursuant to these principles, States enter into treaties of extradition principally for the purpose of bringing fugitives of justice within the ambit of their laws, under conventions recognizing the right of nations to mutually agree to surrender individuals within their jurisdiction and control, and for the purpose of enforcing their respective municipal laws. Since punishment of fugitive criminals is dependent mainly on the willingness of host State to apprehend them and revert them to the State where their offenses were committed, 5 jurisdiction over such fugitives and subsequent enforcement of penal laws can be effectively accomplished only by agreement between States through treaties of extradition.

Desiring to make more effective cooperation between Australia and the Government of the Philippines in the suppression of crime, 6 the two countries entered into a Treaty of Extradition on the 7th of March 1988. The said treaty was ratified in accordance with the provisions of Section 21, Article VII of the 1987 Constitution in a Resolution adopted by the Senate on September 10, 1990 and became effective thirty (30) days after both States notified each other in writing that the respective requirements for the entry into force of the Treaty have been complied with. 7

The Treaty adopts a "non-list, double criminality approach" which provides for broader coverage of extraditable offenses between the two countries and (which) embraces crimes punishable by imprisonment for at least one (1) year. Additionally, the Treaty allows extradition for crimes committed prior to the treaty's date of effectivity, provided that these crimes were in the statute books of the requesting State at the time of their commission.