In the two death penalty cases before the court, both from Texas, one examines information given to jurors while the other questions whether the state properly measured intellectual capability of the accused.

Here in Canada, capital punishment was officially abolished in 1976. The last person to be execuited was at Toronto's Don Jail in 1962.

"The Supreme Court cases this fall are addressing the brokenness of the judicial system," said Karen Clifton, executive director of the Catholic Mobilizing Network to End the Death Penalty.

She said these cases "address the most troubling aspect of the death penalty, which is disproportionately used on vulnerable populations."

Buck v. Stephens will be argued before the court Oct. 5, two days into its new term. It reviews the 1995 sentencing of Duane Buck, who was given the death penalty for the 1995 murders of his ex-girlfriend and another man.

Buck's guilt or innocence is not at stake; called into question is whether he was given a fair sentence. That's because during the punishment phase of his trial, the witness statement of a psychologist, called forth by the defense, said that because Buck is black, there was a stronger likelihood that he would present a danger to society.

Buck's lawyers will argue that this comment held particularly strong weight, especially since Texas law states the imposition of the death sentence must come from a unanimous jury decision that the defendant would pose a threat of future danger.

Texas has acknowledged the error based on similar testimony by the same psychologist, Walter Quijano, in six other cases and promised to re-examine Buck's case but never did.

Sherrilyn Ifill, president of NAACP's Legal Defense and Educational Fund, which is representing Buck, said the bottom line in the case is that racial bias played a role in Buck's sentencing. The 20-year-old case still speaks to what is happening in our country today, she said in a Sept. 30 teleconference with reporters.

Buck is seeking "a new colorblind sentencing hearing," added Kate Black, a NAACP attorney.

The other death penalty case before the court in October is Moore v. Texas where the plaintiff, Bobby James Moore, claims he is intellectually disabled, a claim the state appeals court has rejected. Moore was given the death sentence for his conviction in a 1980 murder of a grocery store clerk during a botched robbery, but his attorneys argue the state used outdated medical standards in their evaluation of Moore's mental state.

If the eight-member court gives a 4-4 ruling on the two cases, the men will be executed since the lower courts and the appeals courts ruled against them and those decisions will stand.

Voters in California, Nebraska and Oklahoma will look at the death penalty as referendum issues.

In Nebraska, lawmakers voted in May 2015 to repeal the death penalty and overrode Gov. Pete Ricketts' veto of their measure, but the measure has not been enforced because it is being put to the voters. They will have to decide if they want to retain the lawmakers' repeal of capital punishment or vote it down.

California has an initiative to replace the death penalty with life in prison without the possibility of parole. Oklahoma has a more nuanced ballot measure – asking voters if they want to add the death penalty to the state's constitution, which would make it clear that if one method of capital punishment is declared invalid or unconstitutional, another method could be used.

Clifton, whose group has been working closely with the state Catholic conferences where the death penalty is coming up for vote, said there is "no question this election is an important possible tipping point for the death penalty." If Nebraska retains the repeal on its use and California repeals the death penalty, she said, it will "show that the Americans are turning away from the death penalty. The end is in sight."

In Oklahoma, she said, the "surface is just being scratched," but she hopes the "ground is being tilled for future legislative reform."

During a Sept. 29 news briefing in Lincoln, Nebraska, across from the state Capitol, Father Doug Dietrich, pastor of St. Mary's Catholic Church in Lincoln, said priests across the state were gearing up to address the issue from the pulpit in the weeks before the vote.

"We are taking a principled pro-life stance and proclaiming that we do not need the death penalty," he told reporters.

Clifton similarly said state victories against the death penalty "would also be a very big pro-life win for this country at a time when the dignity of life is being challenged on many fronts. It would show that even the guilty have dignity and a right to life," she added.

California's bishops have urged voters to support the initiative to outlaw the death penalty and to say no on a proposal to speed up the judicial review of death penalty cases, saying: "Any rush to streamline that process will inevitably result in the execution of more innocent people."

In an Aug. 21 statement, Oklahoma City Archbishop Paul S. Coakley said Oklahomans need to consider if they want to "retain a form of punishment that ratchets up the level of violence, is susceptible to misapplication and is corrosive of the values of our culture."

"Recent trends and statistics about the application of the death penalty as well as the alarming incarceration rates in our state point out the urgent need for criminal justice reform in our nation and in our state," he wrote.

The nation has mixed views on the death penalty. According to the Washington-based Death Penalty Information Center, 30 states have the death penalty and 20 do not.

For the first time in four decades, public approval of capital punishment is decreasing. A Sept. 29 poll by the Pew Research Center that shows that 49 percent of Americans favor the death penalty for those convicted of murder and 42 percent oppose it – which puts opposition to the death penalty at its highest level since 1972. In 2015, 56 percent of Americans supported the death penalty and 80 percent favored it. The numbers in support of the death penalty were much higher in the 1990s. In 1994, 80 percent of Americans favored the death penalty and only 16 percent were opposed to it.

The recent poll, based on telephone surveys from Aug. 23-Sept. 2, shows more support for the death penalty from white mainline Protestants – 60 percent support it and 31 percent oppose – than Catholics where 43 percent support the death penalty and 46 percent oppose it.