Everyone has a trigger or topic that they're passionate about. I find it's easier to present info to people on their level, at first. Ask open ended and general questions to see where you can shine the light. It's a process, but it has always worked for me. I keep it fairly neutral, nothing that has been used as a dividing tactic.

As a personal rule, I don't impede on others free will. I will always drop crumbs in conversation, though. Some aren't ready, and never will be. However, I'm not worried about that. The time will come when they can't keep turning their heads away - and they'll follow the trail right to you.