GUADALAJARA, Spain (Reuters) - Painfully aware that his advancing illness will eventually leave him on life support, Spaniard Mariano Lopez has his hopes pinned not on a cure but on a parliamentary bill that would allow him to meet death on his own terms.

FILE PHOTO: Mariano Lopez, 49, who was diagnosed with amyotrophic lateral sclerosis a year ago, gets his hair combed by his sister Gema after physical therapy in Alovera, Guadalajara, Spain, November 30, 2018. REUTERS/Susana Vera

The government expects to make Spain the fourth country in Europe to decriminalize euthanasia and assisted suicide before its terms ends in 2020.

Right now, helping someone end their life carries a jail term of up to 10 years, and while there are still pockets of resistance in the traditionally Catholic country to dispensing with that penalty, for Lopez the debate is over.

The 49-year-old former businessman was diagnosed with amyotrophic lateral sclerosis (ALS) just over a year ago. He can no longer walk or move his right hand, the first stage of a degenerative process in which sufferers lose the ability to speak, eat and finally breathe.

“It advances rapidly ... When a moment comes I want to have the option of deciding whether the life as it is offered to me, is worth it. And if it’s not, I want to end it,” Lopez told Reuters in a soft voice, his speech slightly slurred.

The Catholic Church - long a lodestone for public opinion in Spain - considers euthanasia to be morally wrong, and the main conservative opposition People’s Party (PP) also wants it to remain a criminal offense.

But the church’s influence has been on the wane ever since Francisco Franco’s dictatorship ended in 1975.

The most recent national opinion poll taken last year showed 84 percent support for euthanasia, and most parties other than the PP have said they will back the minority Socialist government’s demineralization bill.

The previous Socialist administration demonstrated its liberal credentials in 2005, when Spain became the third country in the world to allow same-sex marriage.

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‘I DREAM I’M RIDING A BICYCLE’

Euthanasia has long grabbed public attention in Spain, which has the world’s second-highest life expectancy, and more notably so since Oscar-winning Spanish film ‘The Sea Inside’.

The 2004 film was based on the story of Ramon Sampedro, a paralyzed man who for decades campaigned for the legal right to die. Courts denied him that right but he committed assisted suicide nonetheless.

This is set to change, but Lopez’s hopes for the bill’s quick passage are mixed with concern that case-by-case evaluations it proposes could be a hindrance when the time comes to decide.

He calls euthanasia “an intimate process”, leaving a person free to end a life that has become physically or psychologically unbearable, and would not say how he would proceed if it remained illegal.

ALS, also known as Lou Gehrig’s disease, destroys neural links between the brain and the muscles. Most sufferers die within 3-5 years and it affects about 4,000 people in Spain.

A year ago, Lopez worked, played golf and cycled, seven months ago he could still drive a car. Now he relies on an electric wheelchair and his father, 78, helps him dress. Breathing problems have become a torture, he says.

“In my head, I dream I’m riding a bicycle, going somewhere, but the truth is I can’t even go to the bathroom by myself,” he told said at his sister’s home outside Madrid where he moved after his diagnosis.

Lopez plays with his niece who likes to press buttons on his wheelchair, exchanges jokes and small talk with his physical therapist and doctors, and says he wants his family to see him strong, “so they can move forward”.

His 46-year-old sister Gema has not yet come to terms with the brother’s decision, but says his bravery must be respected.

“If he wants to go on his own terms, it will be done so, no matter what anyone thinks or says,” she said.