It's not syllogistic as there are three points I'd actually point out, but I appreciate that you're the first person to actually ask my stance, so I'll answer.
Stance: Abortion, among other options for pregnancy and birth related care, should be legal and accessible because:
1) There is no medical or legal precedence for "inescapable somatic subjection" (term defined below)
2) Individual morality is just that -- individual
3) One cannot consent to pregnancy on the night of having sex
To point one:
inescapable: unable to be avoided or denied
somatic: relating to the body, especially as distinct from the mind
subjection: cause or force to undergo (a particular experience of form of treatment).
Denying the legality and accessibility of abortion creates a state of inescapable somatic subjection for the pregnant person that is unseen in any other branch of law and medicine.
If a pregnancy cannot be ended by choice, it is inescapable. For roughly nine months, the pregnant person will be unable to avoid or deny the fact that they are pregnant, a fact which affects every part of their lives. While birth at the end of nine months is certainly an end to a pregnancy it is not an escape from or denial of pregnancy anymore than an end of a prison sentence is an escape from or denial of prison. It is a conclusion of a state during which there was no other option to be had.
In no other instance do we legally demand an individual give of their organs and body to keep another person alive, regardless of cause or relationship. We do not legally require fathers to donate livers to children, even when those children would die. Even if the father himself was the cause of the child needing a new liver, we do not require him to give him the liver. We don't even require the dead to give up their organs for the sake of the living, as organ donation is voluntarily and must often still be okayed by living relatives.
In no other branch of law or medicine do we treat any other consequence as inescapable unless a crime was committed. We do not forbid medical treatment for smokers that develop lung cancer, we do not withhold the assistance of the fire department from those who chose to live in fire-prone areas, and we do not withhold police assistance from those who accidentally leave their doors unlocked and are stolen from. Pregnancy is the only condition where some see it justified to say "because you made a 'bad' decision, you are now trapped in your consequences without escape". This a logical inconsistency deriving from the perceived superiority of certain individual's morality, which brings me to part 2.
To summarize this point: We do not legally demand organs from anyone for any reason and therefore have no justification in demanding the use of a uterus for any reason. We do not refuse to treat unwanted consequences based solely on the initial decision, so we there have no justification to deny abortion care because of a previous decision to have sex.
To point 2:
To say it bluntly, individual morality is irrelevant outside of the choices of that particular individual and cannot be used to force the decisions of others. Sure, vegans may go around screaming their own morality in the faces of the not-vegan, and they have the right to do so, but that is where the discussion ends. They do not have the right to enforce the vegan lifestyle through law. The pro-choice mindset essentially says "regardless of my personal morality regarding abortion, I acknowledge that it is not my place to make the decision for others." This seems to be where I keep losing people. Bones's insistence that I clearly speak to where I think the lines regarding abortion should be drawn has repeatedly missed the fact that my stance is that I (and everyone on else on this thread) should not be the ones drawing the lines. All pregnancy and birth related decisions should be left to the pregnant person and their circle of trusted, chosen people (doctors, clergy, family, etc). Uneducated opinions from the general public and the government offer no help. They are nothing but people repeatedly insisting that their morality, their definition of life, their perception of how life should be lived, matters more than the person than that of the person making the decision.
Apart from saying "I would allow the doctor and mother to make a decision" I haven't answered Bones's increasingly gory questions because they are irrelevant to my foundational point. If it not my pregnancy, then what I "would allow" is irrelevant to the decision being made. If it is my pregnancy, then Bones's opinions on what should be allowed would be irrelevant. The pro-choice stance is essentially one giant concept of "mind your own business and let those impacted by and educated on the decision make the decision."
There is no consistent opinion on abortion across the spectrum of humans, both in terms of physical location and time, so an appeal to "morality" offers no universal standards by which we should be making any decisions other than how we as individuals choose to live our own lives.
To summarize: We all have a right to our own morality. None of us have a right to force others to live by our morality. There is no universal standard regarding abortion to point to, so all morality cannot be used to proscribe the actions of others -- only ourselves.
To point 3:
Inevitably, when I say "pregnancy is inescapable" one of two replies come up. The first is "birth is the escape", which was already addressed above. The second is some variation of "you consented to pregnancy when you consented to sex." This is demonstrably false.
To consent is to "give permission for something to happen." There are two physical steps that are required for a pregnancy to occur. The first is that there must be an egg ready to fertilize. The second is that there must be a sperm to do the fertilizing. For simplicity's sake, let's assume the sperm-related step was consensual -- both man and woman agreed to have sex, and now there is sperm available for fertilization. But how do I, as a woman, consent to giving my egg?
Physical processes cannot be consented to -- I cannot give permission for my hair to grow, I cannot give permission for my stomach to digest, I cannot give permission for my ovaries to release an egg. "Giving permission" by definition implies that my say over something matters. Biological processes do not hinge on a person's say -- they happen whether or not we wish them to. They therefore cannot be consented to.
So, if two steps are required for pregnancy, and one step is impossible to consent to, pregnancy can never be consented to. It is a natural process outside of anyone's complete control, as proven by the multi-million dollar fertility industry. It makes no more sense to tell a pregnant person "you consented to being pregnant" than it does to tell a bald man "you consented to being bald." We can accept that pregnancy is a consequence of sex, but as discussed above, there is no precedence for denying treatment for said consequence.
Consent regarding pregnancy then, is an ongoing day to day acceptance, not a one-and-done deal made on the night of sex. I can continuously consent to the ongoing process of pregnancy, but I can also not consent to the ongoing process of pregnancy and seek to terminate it. Unless we seek to treat sex like a crime, and lock a woman into the inescapability of pregnancy, consent must be continually given.
To summarize: pregnancy is a biological process that cannot be consented to in a single night -- continued permission must be given for consent to be present. If continual permission is not given, the option to terminate must be present or the pregnancy has become the inescapable somatic subjection in point 1/
To summarize my stance as a whole: There is no legal or medical precedence to render pregnancy as inescapable somatic subjection by denying abortion access. Pregnant people must always legally be allowed to seek termination if that is their desire. Moral discussions regarding the methods and timing of abortion are fine things for individuals to have, but irrelevant in the grand scheme of the decisions pregnant people will be faced with.
