So here is my objective analysis on this subject.
Reality 1: We cannot prove scientifically in the existence of a soul. There are many people that do not believe in the existence of a soul. Therefore, any argument around abortion that discusses a soul is religious argument, not a moral one.
Reality 2: A person is more valued than a non-person life. You don't get charged for murder for shooting a dog. It's not OK to eat a dead human being. For this discussion, we will define a Person as a being that is able to have rational thought, and is self-aware. A Person has more value than a living being that does not.
Reality 3: An embryo does not have self-awareness or rational thought.
Reality 4: For this analysis, we will use Unborn to collectively refer to embryo / fetus. Every Unborn, if it is genetically sound and implanted in a healthy mother, has the capability to develop into a Person. Tragically, not every Unborn does, but the capacity is there. Because of this an Unborn is different than every other non-Person living thing. There are no other living things on this earth that have the capacity to become a Person other than an Unborn. Miscarriages can be exceptionally tragic. They can cause great distress to the mother and other family on the loss of the Person that was expected.
Reality 5: We do not know when rational thought begins. It very likely begins prior to birth, but it is difficult to measure. One interesting note here is that Navajo have a celebration of the baby's first laugh as proof that the baby is capable of rational thought, and when the baby really achieves Personhood.
Reality 6: In states where abortion is legal,, the mother has the right to determine Personhood of the Unborn. A woman could be walking across the street to get a legal abortion when she is hit by a drunk driver that ends the pregnancy, and the driver can be charged with vehicular manslaughter.
Reality 7: Reasonable people can disagree about the Personhood of the Unborn. It is difficult for most religious people to make an argument about early Personhood without talking about the soul, which some people do not believe in. It is insensitive and intolerant for non-religious people to dismiss people's beliefs about the soul of an Unborn. People that come from two different places of underlying assumptions can reasonably achieve two different conclusions without being intellectually dishonest. There is, in fact, a gray area here if we are accepting of a broad collection world-views.
The real question: The difficulty here is that the state should be protecting Persons from harm, even from the Person's mother. From a legal perspective how do we handle this? Where do we draw the line for legal Personhood that needs protection from the state, and why? Conception is a rationally logical choice, since all Unborn could eventually become Persons. So is heartbeat. So is viability. So is birth. Honestly, if you can step back from your Western heritage, so is first laugh. For anyone to call a religious person ignorant for their belief that abortion is murder is intolerant. For a religious person to call anyone ignorant for their belief that abortion is not murder is alsointolerant.
Issue 1: There is grey area here when it comes to a woman's right to her own body and the Personhood of the Unborn. Unborn are special in that they are parasitic to the Mother until birth. There is no bond like the Unborn with its Mother. The state taking a position to protect a Person from its mother is a huge imposition on the Mother. When the state determines that an Unborn is a Person and takes a position to protect the Unborn, the state makes an imposition on a woman's body. What a mess!
Issue 2: Allowing the state to protect Unborn as a Person gives the state power to regulate the body of the mother. This is a scary and sobering thought. Many will argue that it is the right thing to do given the situation, but it is reality.
My position is one that is sure to piss off almost everyone. I am a religious Person, and believe in the soul, and in scripture that tells me that God forms the body of the Unborn in the womb, therefore, I believe that Personhood begins at conception. However, I don't want the state to have the power to regulate a woman's body. I just don't trust them with this power. Once, when this country had stronger Christian convictions, I was more comfortable with that. I am not now. I think that the state, at the federal level, has no place telling a woman what to do with her body. However, I do trust my local government a lot more than I trust the federal government. I think that if you live in a community of people that all believe in the soul, that they are to be trusted more than an unfamiliar federal government.
Therefore, I think that if a woman wants to get an abortion, she should have that legal right if the majority of the people in the place where she lives think that she should. I'm not even sure that this is a good thing to decide at the state level, but maybe the county level. But, in my mind, every abortion is still killing a baby Person. It's as tragic as any other miscarriage in my eyes, and nothing will ever change that in my mind. But I don't see the mother as a murderer, just lost. How can I call her a murderer when she has no respect for the soul?
I will continue to vote pro-life, and support pro-life causes, especially at the local level. But I think that people that conclude that this is the only way to view the world are myopic. Why should my beliefs about Personhood affect the relationship between the state, the Unborn, and mother in San Fran? People in San Fran are crazy, and do not share my values or culture. I'm not willing to go to war with China to end abortion there! Why is San Fran any more important to me than China on this subject?
I think the current situation is about right, although, I would make abortion a county by county issue. The less we, as a country, try to impose our local belief systems on the nation as a whole, the less success we are going to have as a country.