Stephen Colbert's epic pwnage of Andy Schlafly shows how it's done. How effective would that interview have been if Colbert had just hit Schlafly with a lot of politically correct glurge about how Mother/Father God just wants to give us all a big group hug? Instead, Colbert answered Schlafly with Schlafly's own ideas and answered Scripture with Scripture. While no one expected Schlafly to deconvert on the spot, a fence-sitter could easily see how Schlafly applied both the Bible and his own conservative ideas only when they suited him.
Contrast that with an interview that I once watched with an openly gay Episcopal priest who theologically was the fluffiest bunny who had ever fluffed out his bunny fluff. That priest kept whining that he didn't want to talk about the Bible and, in doing so, badly lost a debate that he should have handily won. Since his most vigorous interlocutor was an African-American woman, he could have just reminded her of what the same literal Biblical interpretation that she used against homosexuality would say about both slavery and the role of women. Yet he did not do so, and since he put forth no argument to justify himself, a fence-sitter could reasonably have concluded that no such argument existed.