MONDAY, Oct. 5, 2015 (HealthDay News) -- California Gov. Jerry Brown signed "right-to-die" legislation on Monday that will allow the terminally ill to legally end their lives.

A lifelong Catholic and former Jesuit seminarian, Brown's decision to support the bill passed by state legislators last month could have a significant impact on the right-to-die debate in the United States. Given the size of its population -- nearly 40 million people -- and its influence, California often sets the tone for potentially groundbreaking issues.

"I do not know what I would do if I were dying in prolonged and excruciating pain. I am certain, however, that it would be a comfort to be able to consider the options afforded by this bill," the governor said in a signing statement that accompanied his signature, the Associated Press reported.

In September, state senators voted 23-14 to let doctors prescribe life-ending medications to patients expected to die within six months. The state Assembly had approved the bill earlier in a 43-34 vote.

Supporters believe that California's approval of the measure could add momentum to the adoption of right-to-die laws across the country.

Opponents of the bill include religious groups such as the Catholic Church and advocates for the disabled.

California becomes the fifth state in which people are allowed to legally end their lives. Oregon, Vermont and Washington already have passed laws allowing the practice, and Montana's courts have authorized it.

"I think lawmakers will be more comfortable voting for aid-in-dying, knowing that a big jurisdiction like California has already done so," said Barbara Coombs Lee, president of Compassion & Choices, a national organization that supports the practice. "It's hard for lawmakers sometimes to think about being the pioneers in a social change movement. It will be easier for them to feel that they are one more state coming along in the assimilation of a new medical practice."

The California legislation is modeled after the Death With Dignity law passed by Oregon voters in 1994, which made that state the first in the nation to allow some terminally ill patients to choose the time of their own death.