dressed in sheep's clothing

So this week we took a look at RAIN from 1932 based on the Somerset Maugham short story of the same name. It's funny, I had always viewed this as a pretty tense classic with exciting character details and an interesting message. Yeah, it's got a couple of big holes in it, namely Sadie's religious conversion and de-conversion happening in the blink of an eye. And the preacher character is two dimensional though probably historically accurate. Apparently though, not so much of a hit with the class. I'll admit to a stereotypical fascination with Ms. Crawford, though I am not currently in possession of any postcards or memorabilia. Mommy Dearest ran in heavy rotation on The Movie Channel in the 1980's and was my after-school viewing of choice. So there's that- I'm predisposed to like this film.
But my real reason for showing it was to focus on the antagonist. He has the qualities that a good antagonist should have in order to push your protagonist to a place of change.
First off, the antagonist has society on his side. He or she should be someone who is above reproach. In the conventional sense this means, bosses, tycoons, religious leaders, teacher, parents, kings, politicians of all sorts people in power. But it can also be queen bees of the high school (Mean Girls) or the top of a subculture (mob bosses, video game fanatics). Whoever they are, they're at the top of the food chain in their society and society says they are right.
Your antagonist should think they are the hero of the story. They're doing this for the greater good in their mind. And we should kind of, almost, sort of see their point. They're just trying to preserve the order of things. They may or may not be aware of their selfish reasons, but most likely the way they see it, the protagonist is the real threat. In some cases, like Rain, they believe they're taking their orders from God.
Your antagonist though, will have a fatal flaw; they're not pure of heart. This is what allows the hero to win. In romantic comedies the way this works is "the other guy" that the girl has fallen for generally just wants to get into her pants (or some other variation of exploitation). Our hero is pure of heart, he LOVES her and it is this pure love that allows him to win in the end. It is the lack of a pure heart that always leads your antagonist to see who they truly are and in that moment of realization they are weak and can be destroyed. In Training Day the Denzel Washington character visits the housing project he has terrorized for all these years only to discover that without his power the people no longer fear him. He is shown his true self and forced to flee. Vulnerable, he is trapped in a web he has spun himself, gunned down on his way to the airport. And this is an important detail; most likely your protagonist does not have to kill the antagonist; they only have to show them who they truly are. The antagonist, so horrified by their true identity will self destruct. As it is in Rain where the Preacher, after presumably raping Sadie, can't live with himself and wanders out into the ocean and cuts his own throat. Good times!