By now, pretty much everyone has heard about Walter Palmer, the American dentist who killed famous Zimbabwean lion Cecil. Since news of the allegedly illegal killing started to spread, the public reaction has been remarkably hostile. For a while, it wasn't clear whether Palmer would face any legal consequences for his alleged actions. Late Friday, however, it was revealed that the Zimbabwean government has asked the United States to extradite Palmer. That's a significant development.
Whenever the alleged perpetrator of a crime is physically outside the prosecuting nation's boundaries, there are practical obstacles to prosecution. Although a nation can theoretically prosecute someone "in absentia," for practical purposes a conviction won't have any real effect unless that nation's government has physical control over the defendant. (This is one reason why, for example, nothing meaningful came of a Malaysian court's 2012 prosecution of George W. Bush and other American officials for war crimes.)
When a nation wants to bring charges against someone who's physically outside of its borders, it typically uses a process called "extradition," through which it asks the other nation to arrest the person and transport him to the prosecuting nation to face the charges. Many nations have extradition treaties with each other. These are agreements providing that if certain conditions are met -- for example, if proper procedures have been followed in the prosecuting nation and the charges are serious enough -- the defendant will be extradited from the "requested state" to the "requesting state" for prosecution.
Extradition can be a burdensome and expensive process. Multiple government agencies from each nation will often be involved, and the process can require several rounds of complicated procedures. The defendant, after being arrested in the requested state, can generally challenge whether his extradition would be consistent with the applicable treaty and any other governing rules, and may have the right to appeal an extradition decision.
For all of these reasons, nations don't always go to the trouble of seeking extradition, especially for relatively low-level offenses. When the Palmer case was first publicized, I had doubts as to whether Zimbabwe -- which does have an extradition treaty with the United States--would really invoke it.
Now that it has, though, there's a strong likelihood that it will be successful and that Palmer will be extradited. The bar for extradition is a low one. The requesting state doesn't have to prove that the defendant is actually guilty, because having such a requirement would essentially transfer power over the case to the requested state.
Instead, the requesting state generally only has to demonstrate that the proceeding itself is a legitimate one that has been properly instituted and that the charges qualify as extraditable ones. In the US-Zimbabwe extradition treaty, the primary applicable requirement is that the offense be punishable in both nations by imprisonment for more than one year. (The punishable-by-more-than-one-year requirement is a common one in extradition treaties; in the U.S., that line generally distinguishes felonies from misdemeanors, so that in essence only felonies are extraditable. The requirement that this must be the case in both nations is called the "dual criminality" requirement -- it's also common, and ensures that someone can't be extradited to face prosecution for something that's not a crime in the requested state.)
Those requirements appear to be met, although there will probably be legal wrangling over issues such as whether the particular charged conduct would constitute a felony in America. Palmer and his lawyers may have to resort to the next line of defense in extradition cases, which is essentially political. Political considerations can definitely play a role in extradition decisions. The requested state may have concerns over how the defendant will be treated if extradited; countries without capital punishment, for example, may refuse to extradite a defendant facing the possibility of that penalty in the requesting state, or may condition extradition on the requesting state's agreement not to seek the death penalty. Such considerations may be permitted by the treaty itself, but even if not the requested state may value protecting its own citizen more than honoring the treaty in a given case.
The problem for Palmer is that the political considerations appear to weigh at least as strongly against him as the legal ones. Unlike the Amanda Knox case, in which many Americans felt that Knox was being treated unfairly and would have strongly opposed any decision sending her back to Italy, in Palmer's case the weight of public opinion seems to favor extraditing him to face charges in Zimbabwe. Moreover, declining extradition could be seen as an insult to the Zimbabweans, and could be cited in the future by countries seeking not to honor American extradition requests.
I can't predict what will happen in the case itself; my mastery of Zimbabwean wildlife law is, I admit, less than comprehensive. But it's a good bet that he will indeed end up over there to face his charges.