Although the electric chair has long been a symbol of the death penalty in the United States, its use is in decline due to the rise of lethal injection, which is widely believed to be a more humane method of execution. While some states still maintain electrocution as a legal method of execution, today it is only maintained as a secondary method that may be chosen over lethal injection at the request of the prisoner, except in Tennessee, where it may be used without input from the prisoner if the drugs for lethal injection are not available. As of 2021, electrocution is an optional form of execution in the states of Alabama, Florida, and South Carolina, all of which allow the prisoner to choose lethal injection as an alternative method. In the state of Kentucky, the electric chair has been retired, except for those whose capital crimes were committed prior to March 31, 1998, and who choose electrocution; inmates who do not choose electrocution and inmates who committed their crimes after the designated date are executed by lethal injection. Electrocution is also authorized in Kentucky in the event that lethal injection is found unconstitutional by a court. The electric chair is an alternate form of execution approved for potential use in Arkansas, Mississippi, and Oklahoma if other forms of execution are found unconstitutional in the state at the time of execution.