The Governor of South Dakota said, as he signed a bill outlawing nearly all abortions, that fetuses are the most vulnerable life around and therefore he thinks that his state needs to protect it. He's been given those line by 30 years of rhetoric from Right to Lifers. It makes a very neat sentence, but it's only half of the equation. It's as if he said, "I feel the need to sign this bill because 2+2." If he said, that, we'd all say, "2+2= what? What's the other half of the equation?"
A fetus can not, at this stage of human knowledge, continue to live and grow without using another person's body. That is why it is vulnerable. And the other side of the equation is that when someone's very body is commandeered by another person, we call it slavery. If the Governor of North Dakota had given us the whole equation, he would have said, that because fetuses are vulnerable, he feels the need to legislate slavery.
Here's another class of vulnerable citizens; those who are dying because they need kidney and liver transplants. Like fetuses, they can only continue to live and thrive if they can have the use of someone else's body. To my mind, they are even more vulnerable than fetuses; not only because they are aware of their dying and are all too often leaving responsibilities, joys, and loves, they are more vulnerable because there is no chance that mandatory kidney and liver donations will be legislated in order to save their lives.
If you put both of these stories together, you get this. A woman who is unwillingly pregnant in North Dakota can (if courts go their way) be forced to donate her body to this growing fetus. She will, if she is a responsible person...or perhaps she will be forced by law to do this, too, cease to smoke or drink alcohol, watch her weight gain, loose her figure, go to repeated doctors appointments, endure morning sickness, take insulin if she needs it, go on bedrest if prescribed, deal with backaches, peeing in the middle of the night, high blood pressure, and eventually, labor and delivery, a natural occurrence, but one with no small amount of pain, danger, drama, and damage to her body. She will be required to go through this by law, to save the life of the fetus, and give birth to the baby. And if the baby is born needing so much as a drop of blood, neither she nor the baby's father can be forced by law to give it, even if the baby will die for the lack.
The reason the baby's father (or any other relative, including the mother) will never be forced to donate a part of their body, even an easily accessed and replaced part like blood or bone marrow to that baby is because in this nation, we value human freedom. And we understand that if one is not free to give or not give of one's own body, one is not free.
If abortion is murder, than mandatory motherhood is slavery. Most of us would decline to enslave another, even at the cost of our lives, and this would be a proper ethical decision. We can't use the bodies of others to save our lives, we must count on them to give freely of their most precious possession, their life, their body, their suffering. It makes us vulnerable to have to count on the love and goodness of others. There's nothing about a fetus which gives it more rights than a baby, child or adult.