Edward Snowden, a former US National Security Agency (NSA) contractor, has been charged with committing espionage against the United States, among other crimes, by the US government.

Officials confirmed on June 21 that a sealed criminal complaint had been lodged with a federal court in the US state of Virginia, and that a provisional arrest warrant had also been issued.

Snowden has been charged with the theft of government property, unauthorised communication of national defence information and willful communication of classified communications intelligence information to an unauthorised person, the document says.

As of June 27, the whistleblower was reported to be hiding in the transit zone of Sheremetyevo airport in Moscow, Russia's capital. Snowden fled there from Hong Kong, where he had initially flown after he leaked documents relating to widespread US surveillance programmes in early June. He has applied for asylum in Ecuador, where authorities say it will take at least two months to make a decision on whether or not to allow him to seek refuge there. Venezuela has stated that if Snowden were to request asylum there, it would "almost certainly" shelter him.

The US, meanwhile, has suspended Snowden's US passport and submitted extradition requests to both China and Russia for Snowden's return to the United States to face trial. The US government has also threatened Ecuador with punitive measures - including the suspension of preferential trade agreements - if it provides Snowden with political asylum.

Process

International extradition is the formal process whereby a person who is in one country is surrendered to another country's authorities to be either tried for a crime or to serve their sentence, in case the person has already been convicted.

The process can generally occur only if there is a formal extradition treaty in place between the two countries in question. Once a formal request for extradition is made, the country where the alleged criminal is located will have the option to either honour it or reject it on grounds specified in the two countries' extradition treaty.

The US does not have an extradition treaty with Russia or China, but it has had one with Ecuador since 1873.

Extradition requests can be refused if it is believed that the charges against the person are political in nature (the US-Ecuador treaty includes such a clause); if the host country does not approve of the punishments (including the death penalty, or the possibility of torture) that the person may face; if there is dual jurisdiction and the person is liable to be tried under the country's own laws; or if the person is a national of the country from which extradition is being sought.

Under US law and policy, a formal extradition request will consist of an affidavit from a prosecutor explaining the details of the case, copies of all relevant US laws alleged to have been broken, certified copies of arrest warrants and/or legal judgments (in case the suspect has already been convicted in a US court) and any evidence that was used to establish the case against the suspect.

These documents are then translated and submitted to the US embassy in the country from whom extradition is being sought. The US mission in the country will then forward it on to the relevant authorities.

The US Department of Justice (DoJ) notes that "appeals and delays are common", even once documents have been submitted to the relevant ministry in the foreign country, as suspects will often have the right to review extradition orders against them through that country's own legal systems.

Once all reviews and appeals have been exhausted, the country will pass a final judgment on whether or not to extradite the suspect to the United States.

'Alternatives to extradition'

Significantly, even if the country chooses not to extradite the suspect to the United States, US DoJ policy does allow for several "alternatives to extradition".

Most notably, the DoJ is prepared to authorise the abduction of suspects against their will to the United States. Citing a 1992 Supreme Court verdict, the DoJ says that criminal defendants can be tried in the United States "even if the defendant was abducted from a foreign country against his or her will by United States agents". Prosecutors must receive "advance [DoJ] approval" before "abducting defendants from a foreign country".

The 1992 case related to the "forcible kidnap" by US agents of Humberto Alvarez Machain, a Mexican resident and citizen who was alleged to have been involved in the kidnapping, torture and murder of US Drug Enforcement Agency agents. In what was a landmark case, the court upheld that "the fact of respondent's forcible abduction does not prohibit his trial in a United States court for violations of this country's criminal laws".

US DoJ policy also allows for the use of a "lure", defined as "using a subterfuge to entice a criminal defendant to leave a foreign country so that he or she can be arrested in the United States, in international waters or airspace, or in a third country for subsequent extradition, expulsion, or deportation to the United States".

Other measures that may be used include revoking the suspect's US passport (possibly resulting in his or her loss of lawful status to be present in the host country), a request for deportation rather than extradition, the pursuit of an Interpol "Red Notice" (which functions as an international arrest warrant, within certain limits) and, as a last-ditch option, a request for the suspect to be tried in the host country's court for the crimes that the US authorities allege they committed.

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