No life penalty in Spain

Hi.
Thanks to an Irish friend, last week I found out that Spain and Portugal are the only two countries in the European Union without life penalty. For American readers: we neither have death penalty.
Why? I think that's in reaction to the dictatorships both countries suffered till the 70's.

Now in Spain we have a hard debate because the European Court for Human Rights, in Strasburg, recently said that Spanish courts can't aply a doctriny called Parot against the prisoners who where condemned before that doctriny was first applied in 1.996. According to that doctriny, a prisoner can spend more years in prison, because the reductions are applied to the whole penalty, and not only to the 30 years limit a person can spend in prison here.

Yesterday I read El Mundo, a Spanish newspaper from the right wing. That way, I knew that Inés del Río ETA terrorist (terrorism is a method of fight that seeks to promove terror between enemies, with bombs or murders, but avoiding open fights against enemy; and ETA is the terrorist organization that used to fight for the independence of the Basque Country from Spain and France, but it never used to attack France 'cause they used to hide in that country), who has been the first prisoner free thanks to Strasburg, killed 24 persons and has spent only 399 days in prison for each murder.
It's a hard debate, because another guy who killed outside a disco in Navarra a guy from my city, Donostia, has been condemned to 18 years because of that murder. I mean, if you start with one, why don't kill all ur list of enemies, if there's no life penalty? Or why using a gun when u can kill more people with a bomb and spend not many more years in prison?

It' a hard topic, and there's another complication: most of the serial killers in Spain belong to ETA, and now there's a peace process, well, ETA said two years ago it would kill nobody else anymore, probably because they were weak because of Police work and the popular support for ETA was much lower than years ago.
So if we punish serial killers harder than single killers, in most of cases we're punishing ETA members, and they stopped killing, and we all want they never kill again.
So, what shall we do?