A federal judge ruled California's death penalty unconstitutional on Wednesday, describing the unpredictable delays as a violation of the Eighth Amendment's protection against cruel and unusual punishment.

The ruling by U.S. District Judge Cormac J. Carney was in a case brought by a death row inmate against the warden of San Quentin state prison.

"Inordinate and unpredictable delay has resulted in a death penalty system in which very few of the hundreds of individuals sentenced to death have been, or even will be, executed by the State," wrote Carney.

Carney stated, "As for the random few for whom execution does become a reality, they will have languished for so long on Death Row that their execution will serve no retributive or deterrent purpose and will be arbitrary."

A death row inmate in California will likely wait at least 25 years before his execution becomes even a realistic possibility.

The legal petition was brought by Ernest Dewayne Jones, sentenced to die in 1994 after being convicted of raping and murdering his girlfriend's mother.

Carney wrote that since the death penalty system was adopted by California voters 35 years ago, more than 900 people have been sentenced to death, but only 13 have been executed. Currently there are 748 inmates on death row, with others dying from natural causes or suicide. More are sentenced to death than have been removed from death row.

Carney wrote, "[T]he current population of Death Row is so enormous that, realistically, California will still be unable to execute the substantial majority of Death Row inmates. In fact, just to carry out the sentences of the 748 inmates currently on Death Row, the State would have to conduct more than one execution a week for the next 14 years."

Carney's decision vacates Jones's death sentence. The case will go to appeals and it is expected it will reach the U.S. Supreme Court.

"I'm hopeful that this decision will quicken the gathering momentum toward abolishing this cruel, inhuman and degrading practice in the United States once and for all," said Steven W. Hawkins, Amnesty International USA executive director. "More than a third of U.S. states have now abolished capital punishment and we will not rest until the remaining follow suit. The U.S. cannot be a country that truly values human rights as long as it continues to execute prisoners."

Eighteen states have abolished the death penalty; 32 states still have the death penalty. Six states -- Alabama, Florida, Missouri, Oklahoma, Texas, and Virginia -- have accounted for about two-thirds of all executions since 1972.

In 2012, a proposition to end the death penalty in California was defeated at the polls, with 53 percent of voters turning it down.

Carney's decision comes as methods to carry out executions are undergoing scrutiny. In 2011, the European Union banned the export of lethal-injection drugs because of activist pressure, fear of lawsuits, and ethical obligations. That decision severed supplies to U.S. prisons and prisons have had difficulty obtaining supplies since.