A measure to abolish California's death penalty qualified for the state's November ballot this week, setting the stage for a sure-to-be-divisive debate that could lead the nation's most populous state to repeal capital punishment 40 years after it was approved by two-thirds of the California electorate. Should the measure pass, California would join 17 states that have repealed the death penalty. Here's what you should know:

How would this measure change the law?
The initiative would reduce the maximum criminal penalty in California from execution to life in prison without the possibility of parole. Currently, California has 723 inmates on death row, although the state hasn't put anyone to death since 2006, when a judge halted executions until death chambers and lethal injection protocols improved. Should this measure pass, death row inmates would return to the general prison population and be expected to work during their life sentences, with their wage earnings going to crime victims.

Why now?
It all comes down to finances, says Maura Dolan at the Los Angeles Times. A study released last year revealed that in cash-strapped California it costs $183 million more annually to administer executions than life in prison without parole. (Prisoners on death row often have costly extended trials and appeals, and are housed in single cells.) California has only executed 13 prisoners over the last four decades, at an estimated cost to taxpayers of $4 billion. Abolishing the death penalty would save California tens of millions of dollars each year, says the Associated Press.

Will it pass?
That's an open question. Californians have typically voted in support of the death penalty — eight in 10 voters favored it in the late '80s, and a 2004 poll found that more than two-thirds of the electorate still support capital punishment. But the tide may be turning. A growing number of conservatives are joining the effort to repeal the death penalty, says Dolan. Even Ron Briggs, who ran a 1978 campaign to expand the scope of the death penalty in California, is backing the repeal effort.

What does this mean nationally?
Should California voters approve the measure, it would continue a trend in declining support for capital punishment. Since 2007, New York, New Jersey, New Mexico, and Illinois have all abolished the death penalty, says Bloomberg, and Connecticut is close to following suit. Nationally, the number of executions have declined from 98 in 1999 to just 43 last year. California has more death row inmates than any other state, says Conor Friedersdorf at The Atlantic. Ending the death penalty there "would be a major victory for those who oppose it," and could set the ball in motion for Florida (402 inmates) and Texas (312 inmates) to reverse course.

Sources: AP, Atlantic, Bloomberg, LA Times, Sacramento Bee