Senator Harry Reid recently re-introduced the “Prevention First Act” which, he said, would decrease abortions by improve family planning and increase the use of contraception. (Summary here, full text here)
This prompted this response today from Dr. William E. May, Senior Fellow of the Culture of Life Foundation:

“The Act is based on the false premise that contraception prevents abortion. The more contraception is available, the more abortions occur because contraception is the gateway to abortion.”

The nub of the argument is that the availability of contraception has led to rampant premarital sex which has led to massive increases in unintended pregnancies which has led to more abortions.
I’m poring over the studies on birth control and abortion, and will try to give you my assessment of the evidence shortly.
Suffice it to say, pro-choice folks believe that contraception is likely to reduce the number of abortions. Their argument: in terms of whether Americans will have sex outside marriage, the cow is out of the barn (and frolicking with that fetching bull across the field.) Given that, more effective use of contraception will reduce the number of unintended pregnancies and abortions.
What do you think?