Libertarians believe that government needs to justify any policy that limits individual liberty. Since the death penalty is the most severe curtailment of liberty that a state can impose on an individual, the state must be able to offer an especially compelling justification for it. This burden becomes even greater when we recognize that the death penalty’s effects reach beyond the person executed. The government must expend significant resources whenever it seeks to execute one of its citizens, which ends up impacting every taxpayer.

Law enforcement always will be a state expense, and thus a burden on taxpayers, so we cannot criticize the death penalty solely on the basis that it costs money. Any libertarian who supports a version of the night‐​watchman state must accept some level of taxation to provide for law enforcement and public safety. The death penalty is not troubling because it costs money, but because it costs significantly more than alternative penalties–such as life in prison without parole–that are equally effective at meeting the state’s responsibility for security.

Capital punishment is expensive because, although any system is fallible, its failures cannot be reversed. In response to innocent people being sentenced to death, American courts have mandated “super due process” in capital cases. The result has been a legal process involving extra preparation, lawyers, and investigators; a separate sentencing phase; and lengthier and more complex appeals. Incarcerating those sentenced to death proves costly, too, since they reside on death row, a higher security area. All together, this process is not cheap: the death penalty ends up costing state governments millions of dollars more than the alternative of life in prison without parole.

Taxpayers most directly feel the cost of the death penalty as a result of local cases. A single death penalty case can devastate the budget in a rural county, which lacks the bureaucracy to handle capital cases with regularity. Counties in Kansas, Utah, Texas, Mississippi, and Georgia all have had to raise taxes to pay for the legal process required by a capital case. After deciding to seek the death penalty, Jasper County, Texas–whose entire annual budget was $10 million–found itself facing over $1 million dollars in expenses just from trying the case. Over the next two years, residents endured a 6.7% increase in property taxes to pay for these expenses.

Even when a conviction leads to execution, which is hardly guaranteed, 10, 15, or even 20 years will elapse before the punishment is carried out. Other than subsidizing attorneys and bureaucrats, do our tax dollars accomplish anything through this policy? There is no evidence that the death penalty makes us safer. States with the death penalty have higher murder rates on average than states without it. Majorities of police chiefs and the public both recognize that the death penalty is an ineffective deterrent.

Instead of making us safer, the death penalty threatens the lives of any innocent citizens unlucky enough to be caught up in a capital trial. Unsurprisingly, like many government programs, the death penalty is prone to error and abuse: since 1973, over 140 individuals in the U.S. have been sentenced to death and later released when evidence of their wrongful conviction came to light.

A variety of factors lead to wrongful convictions, from mistaken eyewitness identifications to police beating suspects into making false confessions. Reforms in the criminal justice system can reduce wrongful convictions, but the problem will persist even if we adopt reforms. Human error and misconduct are inevitable and manifest themselves in ways that are difficult to detect. For instance, a myopic focus on obtaining a conviction leads some prosecutors to suppress key evidence that could exonerate an innocent defendant. Such misconduct puts a defendant in an impossible position: how can you address misconduct if you are completely unaware of it?

The New Orleans District Attorney’s Office has provided abundance evidence of the devastating impact of withholding evidence. Between 1973 and 2002, New Orleans prosecutors obtained death sentences in 36 cases. It turns out that they withheld exculpatory evidence in nine of these cases. This misconduct led to the exonerations of four men, one of whom was John Thompson. Prosecutors charged Thompson with murder and armed robbery, which together allowed them to seek the death penalty. But the prosecution had a problem: blood left by the perpetrator on the robbery victim’s pants did not match Thompson’s blood type. Prosecutors suppressed this and nine other key pieces of evidence in their two cases against Thompson. When Thompson sued, a jury awarded him $14 million damages. The U.S. Supreme Court, however, ruled the DA’s office not liable and took away Thompson’s compensation.

Despite this injustice, at least Thompson escaped with his life. Not everyone is so lucky. A recent report by Columbia Law Professor James Liebman goes into detail how mistakes in Texas likely led to the execution of an innocent man, Carlos DeLuna. A jury found DeLuna guilty of the 1983 murder of Wanda Lopez. DeLuna steadfastly maintained his innocence, and pointed to another Carlos, Carlos Hernandez, as the person who murdered Lopez. Prosecutors dismissed Hernandez as a figment of DeLuna’s imagination. But Hernandez was a real individual, with a long history of violent crime. Hernandez even bragged to numerous people that he had killed Lopez. Unfortunately, the investigative work at the crime scene was so shoddy–no blood samples were collected, for instance–that little usable evidence was available to definitively exonerate DeLuna. So in 1989 Texas executed him.

In light of these cases, reducing the death penalty’s costs through shortening trials and appeals is problematic to say the least. The death penalty in the Jim Crow South–where defendants sometimes were charged, tried, convicted, and executed in a matter of days–was much cheaper than the current system. But it resulted in even more mistakes. Limiting due process in capital cases leads to more fatal errors in a system already known for spectacular mistakes.

In a nutshell, our system of capital punishment is a government program that imposes an extra burden on taxpayers, fails to make us safer, and can kill innocent people. For anyone committed to limited government, it is a difficult system to stomach.