Yesterday, the state of Texas executed a Mexican man following the shooting of a police officer in 1994. However, this execution took place despite the objections of the US State Department (Federal Bureaucracy) and the Mexican Govt; John Kerry even wrote to the Texas Governor to ask for a delay in the execution to no avail. In a country where use of the death penalty is state dependent, this is a great example of the powers of the individual states (as granted to them in the Constitution).
It also demonstrates the continued unwillingness of the Supreme Court to rule on the use of the death penalty. With Supreme Court rulings having the effect of being binding across all states, and the failure in the past to ban the death penalty in the USA (Gregg v. Georgia/Furman v. Georgia), the Supreme Court have settled in recent years for ‘tinkering around the edges’. This means they have placed limits on who can be executed (Panetti v. Quarterman, Baze v. Rees) but avoiding banning the use of the death penalty altogether.