That's one of the biggest arguments in favor of it — that the possibility of death as a punishment prevents people from committing capital crimes. But that's a hard claim to back up. A 2009 study said 88 percent of the criminologists polled did not believe fear of the death penalty prevents capital crimes.
But other research found fewer homicides occurred in Texas in the months before or after an execution. Although some say the model used in that research could have been flawed. The Constitution is also frequently brought up in the death penalty discussion.
Many say it goes against the Eighth Amendment, which protects citizens from "cruel and unusual punishment." Lately, that debate has focused on the method used to execute criminals.
In June of this year, the Supreme Court ruled 5-4 in favor of Oklahoma's use of a controversial drug cocktail used in multiple botched executions. In January, one man sentenced to death writhed in pain for hours before the drug mixture killed him.
The death penalty debate isn't going away. Aside from four years in the 1970s, capital punishment has been permitted in the U.S. since 1790.
Click through to see some of the more notable executions and people on death row:
Notable death penalty executions and people on death row
Breaking down the death penalty debate
Willie Francis, the first known incident of failed execution by lethal injection, was executed on May 9, 1947. He was sentenced to death for the murder of his former boss, Andrew Thomas.
John Wayne Gacy, a rapist and serial killer responsible for the sexual assaults and murders of at least 33 men, was executed in Illinois on May 10, 1994.
Ted Bundy, a kidnapper, rapist, and serial killer responsible for the assaults and murders of dozens of young women, was executed in in Florida on January 24, 1989. His actual victim count remains unknown.
Aileen Wuornos, a serial killer responsible for the deaths of seven men, was executed in Florida on October 9, 2002.
(AP Photo/Peter Cosgrove)
Charles Starkweather, a spree killer responsible for eleven murders, was executed in Nebraska on June 25, 1959.
(AP Photo/Don Ultang)
Timothy McVeigh, responsble for the Oklahoma City bombing, was executed in Indiana on June 11, 2001.
Thomas Provenzano, a convicted murderer responsible for shooting three people, was executed in Florida on June 21, 2000.
(AP Photo/Peter Cosgrove)
Gary Gilmore, responsible for the shooting deaths of two men, was executed in Utah on January 17, 1977.
Stanley "Tookie" Williams, founder and leader of the Crips gang responsible for several murders and other crimes, was executed in California on December 13, 2005.
(Photo by Justin Sullivan/Getty Images)
Teresa Lewis, convicted of murdering her husband and stepson, was executed in Virginia on September 23, 2010.
(AP Photo/Va Dept of Corrections)
William Bonin, a serial killer responsible for a minimum of 21 rapes and murders, was executed in California on February 23, 1996.
Dzhokhar Tsarnaev, responsible for Boston Marathon bombing, was sentenced to death on May 15, 2015.
(AP Photo/Federal Bureau of Investigation, File)
Nidal Malik Hasan, responsible for Ford Hood shooting, was sentenced to death on August 28, 2013.
(AP Photo/Bell County Sheriff's Department, File)
Joseph E. Duncan III, a convicted murderer and sex offender, was sentenced to death on August 27, 2008.
(AP Photo/Kootenai County First Appearance Video Court)
Death row prisoner Coy Wayne Wesbrook is photographed Wednesday, Feb. 3, 2016, at the Texas Department of Criminal Justice Polunsky Unit outside Livingston, Texas. Wesbrook, 58, is set for lethal injection March 9, 2016, for the November 1997 fatal shootings of his ex-wife and another man at her apartment in Channelview, just east of Houston. They were among five people killed during the shooting rampage. (AP Photo/Michael Graczyk)