http://www.opinionjournal.com/extra/?id=110005277

Check out the long analysis of the Roe Effect, the theory that abortions since Roe v Wade have adversely affected the Democratic Party's ability to get votes. Why? Because far more leftists have gotten abortions than right wingers, and most of those aborted fetuses would probably have grown up to vote the same way their parents would have. So the Democratic Party, according to the stats in this article, has denied itself something like 25 million voters.