I think abortion should definitely be legal. That said, I totally understand the point of view that people should not be using abortion as an 'easy' way to avoid (or not take responsibility for) using contraceptives.
I think a combination of educating the heck out of young people on condom/birth control use is one way to combat this... maybe also making abortions very expensive for those not needing it for medical/rape reasons? If it costs someone $500 to get an abortion because they were irresponsible, maybe it will prevent them from making the same (expensive) mistake next time?
Though, I'm a hypocrite on the issue. While I believe in abortion, I'm also _really_ glad I wasn't aborted. When you think that any of us could just as easily not be here with a quick procedure... I guess I'm not comfortable with that aspect. It's not murder... but it's 'close'. I'm sure I'll be beaten to death on this issue