I know EU countries have, in the past, as a condition of extradition required the US to guarantee that the death penalty won't be sought or applied.
EU (& other countries bound by the European Convention on Human Rights) are not allowed to extradite people to countries where they might face a breech of the ECHR, ergo you cannot extradite unless there is a guarantee of no capital punishment.
EU (& other countries bound by the European Convention on Human Rights) are not allowed to extradite people to countries where they might face a breech of the ECHR, ergo you cannot extradite unless there is a guarantee of no capital punishment.