A common tactic of the narcissist is gas lighting. (from the movie Gas Light) Where the narcissist convinces their target that they are going crazy.

The normal person thinks that most people are rational and honest. They cannot conceive of someone lying about the state of things. So, with repeated exposure to the narcissist they start to lose their grasp on reality. As the narcissist continues to push (and they won't ever stop, even on your death bed) the normal person will go insane, have mental and emotional breakdowns, or commit suicide.

Could you imagine destroying someone's grasp of reality? Maybe for a lark, over the course of one party. But a narcissist, once on this path, will continue it until you or they die.

You may say, this can't really happen. Anyone can see through such ploys. But I can tell you that there are a lot of people destroyed from being in a relationship with these people. The narcissist is very good at making it all sound plausible to you. Their lies (well practised) are tailored for you to believe them.

The democrons: We HAVE TO help the poor
The republicrats: We have to be able to afford to help the poor.
Both of these are lies. They are just tailored that one group of people to believe them. The other group of course, knows that the other is false.