Echoing canttestthis in the other reply subtread, the fundamental principle is that we won't hand over our citizens to other countries for things which are not crimes in our own: http://en.wikipedia.org/wiki/Dual_criminality

All of Europe refuses to extradite to the US if the death penalty is a possible outcome: http://en.wikipedia.org/wiki/Extradition#Bars_to_extradition and futher down it mentions "France, Germany, Russia, Austria, the People's Republic of China, the Republic of China (Taiwan) and Japan" flatly refuse to extradite, something that is certainly not true of the US.