Transnational crimes are crimes that have actual or potential effect across national borders and crimes which are intra-State but which offend fundamental values of the international community. The term is commonly used in the law enforcement and academic communities.
The word "transnational" describes crimes that are not only international (that is, crimes that cross borders between countries), but crimes that by their nature involve cross-border transference as an essential part of the criminal activity. Transnational crimes also include crimes that take place in one country, but their consequences significantly affect another country and transit countries may also be involved. Examples of transnational crimes include: human trafficking, people smuggling, smuggling/trafficking of goods (such as arms trafficking and drug trafficking and illegal animal and plant products and other goods prohibited on environmental grounds (e.g. banned ozone depleting substances), sex slavery, terrorism offences, torture and apartheid. Transnational organized crime (TOC) refers specifically to transnational crime carried out by organized crime organizations.
Transnational crimes may also be crimes of customary international law or international crimes when committed in certain circumstances. For example they may in certain situations constitute crimes against humanity.
In failed or failing states
The international community is confronted with an increasing level of transnational crime in which criminal conduct in one country has an impact in another or even several others. Drug trafficking, human trafficking, computer crimes, terrorism, and a host of other crimes can involve actors operating outside the borders of a country which might have a significant interest in stemming the activity in question and prosecuting the perpetrator. Contemporary transnational crimes take advantage of globalization, trade liberalization and exploding new technologies to perpetrate diverse crimes and to move money, goods, services and people instantaneously for purposes of perpetrating violence for political ends.
Moreover, problems of weakened states and transnational crime create an unholy confluence that is uniquely challenging. When a criminal operates outside the territory of an offended state, the offended state might ordinarily appeal to the state from which the criminal is operating to take some sort of action, such as to prosecute the offender domestically or extradite the offender so that he or she may face punishment in the offended state. Nonetheless, in situations in which a government is unable (or unwilling) to cooperate in the arrest or prosecution of a criminal, the offended state has few options for recourse.
Given the limits on the exercise of extraterritorial enforcement jurisdiction, states have developed mechanisms to cooperate in transnational criminal matters. The primary mechanisms used in this regard are extradition, lawful removal, and mutual legal assistance.
Extradition is the mechanism by which one sovereign requests and obtains custody of a fugitive located within the jurisdiction and control of another sovereign. It is an ancient mechanism, dating back to at least the thirteenth century, when an Egyptian Pharaoh negotiated an extradition treaty with a Hittite King. Through the extradition process, a sovereign (the requesting state) typically makes a formal request to another sovereign (the requested state). If the fugitive is found within the territory of the requested state, then the requested state may arrest the fugitive and subject him or her to its extradition process. The extradition procedures to which the fugitive will be subjected are dependent on the law and practice of the requested state.
Aside from mechanisms for the return of fugitives, states have also developed mechanisms for requesting and obtaining evidence for criminal investigations and prosecutions. When evidence or other forms of legal assistance, such as witness statements or the service of documents, are needed from a foreign sovereign, states may attempt to cooperate informally through their respective police agencies or, alternatively, resort to what is typically referred to as requests for “mutual legal assistance” The practice of mutual legal assistance developed from the comity-based system of letters rogatory, though it is now far more common for states to make mutual legal assistance requests directly to the designated “Central Authorities” within each state. In contemporary practice, such requests may still be made on the basis of reciprocity but may also be made pursuant to bilateral and multilateral treaties that obligate countries to provide assistance. Many countries are able to provide a broad range of mutual legal assistance to other countries even in the absence of a treaty.
There can be few issues on which international legal opinion is more clear than on the condemnation of torture. Offenders have been recognised as the "common enemies of mankind"
- Boister, Neil (2003). "Transnational Criminal Law?". European Journal of International Law 14: 953, 967–77.
- Dan E. Stigall, U.S. Department of Justice (2013). "Ungoverned Spaces, Transnational Crime, and the Prohibition on Extraterritorial Enforcement Jurisdiction in International Law". Notre Dame Journal of International and Comparative Law 3 (1). Retrieved 2013-06-11.
- A (FC) and others (FC) (Appellants) v. Secretary of State for the Home Department (Respondent)  UKHL 56.