The death penalty is indeed a deterrent. It is the only way possible to ensure that they well not kill again.
Seriously, I don't know how anyone can argue against that.
The same people who argue that executing one won't deter another have yet to provide proof how giving someone a life sentence has decreased the amount of murders by other killers. If they argue that the death penalty isn't a deterrent for others, the only other option is that a life sentence is a deterrent.
As for what you said, I agree. It deters that person and since that person is the only one on trial, that's all that matters.
When discussing whether or not the death penalty is a deterrent, most people understand that it means whether or not the fear of it deters people from committing a murder. Life in solitary confinement is a deterrent just as much as the death penatly.
There are limits to solitary confinement. By law prisoners are entitled to at least an hour of rec time a few days a week when they have to escorted by guards. They are furthermore entitled to medical treatment which is not done in their cells. Take the case of this lovely person, Thomas Knight. He shall kill no more:
July 17, 1974 – Thomas Knight kidnaps and murders Sydney and Lillian Gans of Bay Harbor Islands. He is immediately arrested.
September 1974 – Knight and 10 other inmates escape from Dade County jail. He is placed on the FBI’s Ten Most Wanted List.
October 1974 – Police believe Knight and another man fatally shoot a liquor store clerk during a robbery for $641 in Crisp County, GA. He is not charged.
December 1974 – FBI agents capture Knight in New Smyrna Beach. He is found with a shotgun and two pistols, all stolen.
April 1976 – A Miami-Dade jury convicts Knight of murdering the couple. He is sentenced to death.
October 1980 – Using a sharpened spoon, Knight stabs and kills corrections Officer Richard Burke at the Florida State Prison in Starke.
March 1981 – Knight is scheduled to be executed after Gov. Lawton Chiles signs his death warrant. A federal judge stays his execution pending more appeals.
January 1983 – Knight is convicted and sentenced to death for the Burke murder.
January 1996 – A federal appeals court overturns his death sentence in the Gans case, ordering a new penalty phase trial.
February 1996 – After a new sentencing phase, Knight is again sentenced to death. He is repeatedly banned from the courtroom because of his disruptive behavior.
March 2006 – With state courts repeatedly affirming his conviction and sentence, Knight’s lawyers appeal to a Miami federal judge.
November 2012 – Six years after the appeal was first filed, Miami U.S. Judge Adalberto Jordan reverses Knight’s death sentence. He orders a new sentencing hearing or life sentences for the convict.
September 2013 – A federal appeals court reverses Judge Jordan, reinstating the death penalty for Knight. “To learn about the gridlock and inefficiency of death penalty litigation, look no further than this appeal,” the court writes.
October 2013 – Gov. Rick Scott signs death warrant for Knight, not for the Miami-Dade murders but for the slaying of Burke. The execution is scheduled for Dec. 3.
November 2013 – The Florida Supreme Court delays the execution, ordering a Bradford judge to hold a hearing to consider whether a new drug used in the lethal injection procedure constitutes cruel and unusual punishment.
December 2013 – The state’s high court lifts the stay of execution after ruling Knight has failed to prove the drug is unsafe. Gov. Rick Scott re-schedules the execution for Jan. 7.
Don't be a dupe.