Those that are wanted to stand trial for alleged criminal or political offences and who seek refuge in another country, may not be extradited under a number of conditions. One condition is if the sheltering country is not party to any extradition treaties and another is; also if the two nations involved do not have diplomatic relations. Extradition proceedings may not be instituted on alleged humanitarian grounds under a variety of circumstances, and finally, those accused of political offences may be exempt under provisions of international law.
Efforts by the USA, in 1993, to extradite the founders of a failed bank which owes a $200 million fine to the government were blocked by the lack of an extradiction treaty with either Pakistan or Abu Dhabi, where the men live. Even in instances where extradiction treaties exist, it has been exceedingly difficult for the USA authorities to get hold of drug dealers or terrorists because of domestic consideration. Colombia, for example, abandoned its extradition treaty with the US as part of a peace deal with the country's drug barons.