I think my favorite answer would be this one when Prof. George responds to Kmiec’s question regarding where the church has presented scientific evidence regarding the humanness of the human embryo.
The magisterium of the Church has made reference to the facts of human embryology in various documents touching on our moral obligations to our brothers and sisters at the dawn of life. (It has done so most recently in the Vatican Instruction Dignitas Personae. See especially sections 4-6.) The authors of these documents have rightly assumed that these facts are not obscure and are easily accessible to anyone who cares to know them. Joseph Biden can read. If he took the teaching of his Church seriously—indeed, if he took seriously the question of the moral status of those beings whose lives are deliberately taken in abortion and embryo-destructive research—he would spend the small amount of time required for him to familiarize himself with the facts.He also has some thoughts on how we should treat those whom we disagree with.
In thinking about what attitude one ought to adopt towards fellow citizens with whom one disagrees about profound issues of right and wrong, all of us would do well to consider the example set by Ulysses S. Grant. Although Grant waged relentless war against Robert E. Lee and his army, the Union general regarded his great adversary as a man of integrity and honor. Indeed, he admired Lee for fighting so selflessly for a cause he believed in, though it was, Grant bluntly said, "the worst cause for which anyone ever fought." After Lee's surrender at Appomattox Courthouse, Grant refused to exult, or permit his men to exult, over his vanquished foe, and (to Lee's astonishment) expressly declined to subject Lee to the humiliation of demanding his sword. Going still further in magnanimity, Grant provided 25,000 rations to Lee's starving army. If after four years of bitter and bloody warfare, General Grant could treat General Lee with such respect, we should be able to treat those with whom we disagree with no less respect, even as we struggle, as we are bound in conscience to do, to defeat them in the arenas of democratic deliberation and decision.