	Introduction

"'Extradition' is the formal surrender of a person by a State to another State for prosecution or punishment." Extradition to or from the United States is a creature of treaty. The United States has extradition treaties with over a hundred of the nations of the world, although there are many with which the United States has no extradition treaty. International terrorism and drug trafficking have made extradition an increasingly important law enforcement tool. Bars to Extradition

Extradition treaties are in the nature of a contract, and by operation of international law, 
[a] state party to an extradition treaty is obligated to comply with the request of another state party to that treaty to arrest and deliver a person duly shown to be sought by that state (a) for trial on a charge of having committed a crime covered by the treaty within the jurisdiction of the requesting state, or (b) for punishment after conviction of such a crime and flight from that state, provided that none of the grounds for refusal to extradite set forth in [the treaty] is applicable. Military and Political Offenses

In addition to an explicit list of crimes for which extradition may be granted, most modern extradition treaties also identify various classes of offenses for which extradition may or must be denied. Common among these are provisions excluding purely military and political offenses. When a foreign country seeks to extradite a fugitive from the United States, dual criminality may be satisfied by reference to either federal or state law. The purpose of the hearing is in part to determine whether probable cause exists to believe that the individual committed an offense covered by the extradition treaty. Extradition for Trial or Punishment in the United States

The laws of the country of refuge and the applicable extradition treaty govern extradition back to the United States of a fugitive located overseas. If the United States has no extradition treaty with the country of refuge, extradition is not a likely option. Although treaty requirements vary, the Justice Department suggests that prosecutors supply formal documentation in the form of an original and four copies of
a prosecutor's affidavit describing the facts of the case, including dates, names, docket numbers and citations, and preferably executed before a judge or magistrate (particularly if extradition is sought from a civil law country) copies of the statutes the fugitive is said to have violated, the statutes governing the penalties that may be imposed upon conviction, and the applicable statute of limitations if the fugitive has been convicted and sentenced: identification evidence; certified documentation of conviction, sentence, and the amount of time served and remaining to be served; copies of the statutes of conviction; and a statement that the service of the remaining sentence is not barred by a statute of limitations if the fugitive is being sought for prosecution or sentencing: certified copies of the arrest warrant (preferably signed by the court or a magistrate) and of the indictment or complaint if the fugitive is being sought for prosecution or sentencing: evidence of the identity of the individual sought (fingerprints/photographs) and of the evidence upon which the charges are based and of the fugitive's guilt in the form of witness affidavits (preferably avoiding the use grand jury transcripts and, particularly in the case of extradition from a common law country, the use of hearsay). The treaty issue most likely to arise after extradition and the fugitive's return to this country is whether the fugitive was surrendered subject to any limitations such as those posed by the doctrine of specialty. Regardless of their view of fugitive standing, reviewing courts have agreed that the surrendering State may subsequently consent to trial for crimes other than those for which extradition was had.
"Extradition" is the formal surrender of a person by a State to another State for prosecution or punishment. Extradition to or from the United States is a creature of treaty. The United States has extradition treaties with over a hundred nations, although there are many countries with which it has no extradition treaty. International terrorism and drug trafficking have made extradition an increasingly important law enforcement tool. This is a brief overview of the adjustments made in recent treaties to accommodate American law enforcement interests, and then a nutshell overview of the federal law governing foreign requests to extradite a fugitive found in this country and a United States request for extradition of a fugitive found in a foreign country.
Extradition treaties are in the nature of a contract and generate the most controversy with respect to those matters for which extradition may not be had. In addition to an explicit list of crimes for which extradition may be granted, most modern extradition treaties also identify various classes of offenses for which extradition may or must be denied. Common among these are provisions excluding purely military and political offenses; capital offenses; crimes that are punishable under only the laws of one of the parties to the treaty; crimes committed outside the country seeking extradition; crimes where the fugitive is a national of the country of refuge; and crimes barred by double jeopardy or a statute of limitations.
Extradition is triggered by a request submitted through diplomatic channels. In this country, it proceeds through the Departments of Justice and State and may be presented to a federal magistrate to order a hearing to determine whether the request is in compliance with an applicable treaty, whether it provides sufficient evidence to satisfy probable cause to believe that the fugitive committed the identified treaty offense(s), and whether other treaty requirements have been met. If so, the magistrate certifies the case for extradition at the discretion of the Secretary of State. Except as provided by treaty, the magistrate does not inquire into the nature of foreign proceedings likely to follow extradition.
The laws of the country of refuge and the applicable extradition treaty govern extradition back to the United States of a fugitive located overseas. Requests travel through diplomatic channels, and the treaty issue most likely to arise after extradition to this country is whether the extraditee has been tried for crimes other than those for which he or she was extradited. The fact that extradition was ignored and a fugitive forcibly returned to the United States for trial constitutes no jurisdictional impediment to trial or punishment. Federal and foreign immigration laws sometimes serve as an alternative to extradition to and from the United States.
This report is available in an abbreviated version, CRS Report RS22702, An Abridged Sketch of Extradition To and From the United States, by [author name scrubbed], which appears without the citations to authority, footnotes, or appendices found here.