Everyone has the right to decide whether or not their life is still worth living. If, for any reason, a person decides they'd rather be dead then they have the right to end their own life. If circumstances make them unable to take that action themselves then they have the right to ask someone else to do it for them, though no one should be obligated to take a life. If their injury or illness is so severe it makes communication impossible, then the decision should fall to next of kin or whoever else was closest to the person.
As for the death penalty, the legal process involved is actually much more expensive than lifetime incarceration. From a purely pragmatic perspective it should be abolished.
Abortion should be an option early in pregnancy. If the mother was ever willing to abort, then it's highly unlikely the infant would have a life worth living. My opinion is different for late-term abortions. Scientific evidence strongly suggests that more developed fetuses (starting around the beginning of the third trimester) are conscious and feel pain, and the methods of late-term abortion are invariably excruciating. At this point I don't care whether the fetus is a human being or something less. I would only support such an abortion if the fetus was found to have a severe genetic defect that would significantly degrade quality of life or kill them anyway.
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You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.