You can decide not to have an abortion.
You can decide that you will not associate with anyone who would have an abortion.
You can take a little doll that looks like someone who has had an abortion, and stick pins it and chant incantations.
Whatever.
What you have no right to do is to decide for someone else if they will have an abortion. Your uterus is your business. Mine is my business.
My sole argument is that if a woman does not want a thing inside her, she has the right to have it removed -- whether it is a blob of undifferentiated cells, a sentient being, or Jesus H Christ himself.
If you want to incubate whatever takes up residence in your uterus, go ahead. But don't tell me that I have to.