Article: Four states in the modern era, Nebraska in 2008, New York and Kansas in 2004, and Massachusetts in 1984, had their statutes ruled unconstitutional by state courts. The death rows of New York and Massachusetts were disestablished, and attempts to restore the death penalty were unsuccessful. Kansas successfully appealed State v. Kleypas, the Kansas Supreme Court decision that declared the state's death penalty statute unconstitutional, to the United States Supreme Court. Nebraska's death penalty statute was rendered ineffective on February 8, 2008 when the required method, electrocution, was ruled unconstitutional by the Nebraska Supreme Court. In 2009, Nebraska enacted a bill that changed its method of execution to lethal injection.

Question: What method of execution did the Nebraska Supreme Court rule unconstitutional?
electrocution