In his commencement address to the University of Notre Dame’s 2009 graduating class last month, President Obama recognized an obvious truth with his statement that pro and anti abortion advocates have certain irreconcilable differences. Those differences were obvious when Obama’s invitation to Notre Dame was subject to controversy and pronounced public disagreement. It was obvious again during the President’s commencement address when anti-abortion advocates vocally challenged the President and were, in turn, vocally challenged by others in the audience. What might not be so obvious, however, is that one of the differences between the two sides of this issue, whether...