who have purposed to overthrow my goings. - Psalm 140.
The concept is that the baby in the womb has not committed any crime and is innocent (except, in some Christian circles, of original sin). The person that the pro-gun and pro-life people plan on aiming their weapons at is a criminal.
It's not really my position, but I've never found it difficult to understand. The one that is harder to reconcile, especially from a religious perspective, is the stance that is at once pro-death penalty and pro-life. I know how they attempt to reconcile it (innocent life needs to be protected in all cases, the death penalty is punishment for taking life only), but if the starting position is that life is sacred, and given that life in prison is cheaper than execution, I still see some points for attack.
ἡ δὲ κἀκ τριῶν τρυπημάτων ἐργαζομένη ἐνεκάλει τῇ φύσει, δυσφορουμένη, ὅτι δὴ μὴ καὶ τοὺς τιτθοὺς αὐτῇ εὐρύτερον ἢ νῦν εἰσι τρυπώη, ὅπως καὶ ἄλλην ἐνταῦθα μίξιν ἐπιτεχνᾶσθαι δυνατὴ εἴη. – Procopius
Ummaka qinnassa nīk!
*MySmiley*
in addition...
*NM*