Let's get a bit meta. I posit that there are certain political discussions where rational debate is entirely useless, because they largely consist of choosing an axiom. Abortion is the most obvious of these - people who believe the right to life begins at conception(usually for religious reasons) are almost universally pro-life, and people who do not are almost universally pro-choice. It is not possible, even in principle, to convince either side of the other's position, because there's no argument that can change an axiom.

It's good to keep our limitations in mind.

Edit: To clarify, I don't claim that rational debate is useless at discussing issues around abortion, I claim it's useless at changing the minds of someone who has a strong position on the issue. The only people I have ever seen switch sides on this issue are politicians(who are obviously lying) and religious converts(which is in principle achievable from rationalism, but which is in practice a pretty rare result).