By using extraordinary rendition, people are able to gather information that might otherwise not be made available to them. For example, if there was ever a case when someone had planted a bomb somewhere and the location was unknown, by use of extraordinary rendition, the location may be revealed to the government who can then appropriately act to diffuse the situation. The torture of one individual therefore can be considered in times of terror when a persons human rights can be infringed for the sake of many. Why should innocent people potentially have to die because it is 'morally incorrect' to torture information out of someone who is believed to be able to prevent a crisis. I understand the argument that suggests that the person may have been coerced/forced into this plan or may be innocent themselves, however, the risk should be justified if they are believed to possess information and there is sufficient evidence that links them to the plot.
No, extraordinary rendition is not justified in fighting terrorism, because it is unfair to a state's autonomy to take people from their state without their approval. Nations should work together as an international community in order to bring offenders to justice. It does not help international relations to have some nations acting unilaterally.
No matter how bad the crime one is believed to have committed or have been accomplices to, there is no excuse for their extraordinary rendition or international transfer. One government should give the right to another to question a detained individual, if they please but to extradite the person is incomprehensible. This should be illegal under international law. In the event that a trial should be held, it should be in the nation of capture of the detained and by the nation holding the detained.