Pro-life argument in the form of systematic logic

I just crafted the following argument for a facebook conversation, and I would like outside input. In particular, I'm wondering if my friends & acquaintances who are trained philosophers could help me find the technical holes in my formal argument. I know I'm not the first to put something like this together, and I certainly won't be the last... but, it was fun!

Argument in favor of pro-life legislation in the United States
1. Our nation promises all humans the right to life and liberty. (Axiom, from the Declaration of Independence)
2. The right to life qualifies all other rights. (Axiom, implied by the Declaration of Independence)
This is the only statement I'll elaborate on just a bit. Life, Liberty, and the pursuit of Happiness are to be granted to U.S. citizens in that order - that is to say, when there is a conflict between one person's life and another person's liberty, the claimant on life has the legal right. You and I have liberty, but that liberty is qualified by the state in important ways - I am not allowed to murder you, and vice versa.
3. The right to liberty is one of those "other rights." (Follows from #1)
4. One person's right to live qualifies each other person's right to liberty. (Follows from #2 & #3)
4a. Each person's right to liberty does not include any right to infringe upon any other person's right to live. (Restatement of #4)
5. A nation that promises rights should defend those rights with the rule of law. (Axiom, probably from Plato's Republic or some other classic I've never read)
6. Our nation should defend the human right to life with the rule of law. (Follows from #1 & #5)
7. Our nation should defend the human right to liberty with the rule of law. (Follows from #1 & #5)
8. Our nation's defense of the human right to liberty should not include any right to infringe upon any other person's right to life. (Follows from #4a & #7)
9. A woman's choice to receive an abortion in any case where her own life is not in mortal danger is a matter of liberty. (Axiom, from the definition of liberty)
10. If a fetus is a human, s/he has a right to life. (Follows from #1)
11. If a fetus is a human, s/he has a right to life that qualifies each other person's right to liberty. (Follows from #4 & #10)
12. The mother of any fetus is in the category of "each other person." (Axiom, from the definition of person)
13. If a fetus is a human, s/he has a right to life that supersedes and qualifies her/his mother's right to liberty. (Follows from #11 & #12)
14. A fetus is a human from the point of conception. (Separate scientific and logical argument, alluded to above)
15. A fetus has a right to life that qualifies her/his mother's right to liberty. (Follows from #13 & #14)
16. Our nation should defend a fetus's right to life with the rule of law. (Follows from #6 & #14)
17. Our nation should defend a mother's right to liberty with the rule of law. (Follows from #7 & #12)
18. Our nation's defense of a mother's right to liberty should not include any right to infringe upon her fetus's right to life. (Follows from #8, #16, & #17)
19. Our nation should defend, with the rule of law, a fetus's right to life from her/his mother's choice to receive an abortion in any case where the mother's life is not in mortal danger. (Follows from #9, #16, & #18)