Since I believe that human life begins at conception, how can I "concede"---what right do I have to "concede"---anything that would be a death warrant for certain human beings? 

What I CAN concede, and many times have, is that reasonable people of good faith can disagree about whether a person worthy of protection exists from conception onward.  This is where Roe v. Wade went off the tracks. I hate to concede it, but I must: New York, California, Ohio, whatever---all have the right to say that abortion is always just fine! As an American, I accept that that's the democratic process. By the same token, it can go the other way, too---and the Roe Court had to turn legal pretzels (and do lasting damage to constitutional law far beyond the scope of abortion) in order to reach the conclusion it did. On this point, read a classic, "The Wages of Crying Wolf," by Jon Hart Ely, who personally supported the right to abortion.  It's worthy of a Pulitzer. May God inspire your search for the truth.