In my experience, most abortion rights proponents are fuzzy (either deliberately or inadvertantly) on what abortion really means for the unborn child. But as Novak points out, science (invoked with such reverence by the left when it comes to the environment) indicates that life begins much, much earlier than almost all abortion rights supporters would concede.
It's ironic that a President and First Lady who identify so strongly with the plight of once-enslaved African Americans -- whose oppressors justified their mistreatment on the grounds that they were somehow less than fully human -- could be so indifferent to the fate of the unborn, who are often mistreated under the same rationale. So indifferent, in fact, that abortion activists are credibly pressing him to repeal the ban on partial birth abortion and the Born Alive Infant Protection Act.
As Novak asks, if there is obviously a natural right to liberty -- well, isn't there a natural right to life, too?
Update: Apparently, even finding a pro-life Democrat in the President's circle to serve as ambassador to the Holy See is proving problematic.