If you don't know of the movie "Gaslight" with Ingrid Bergman and Charles Boyer, find it and watch it. It is a superb suspense film full of mood and character. The focus is on the gradual, deliberate manipulation of a wife by her husband, to convince the wife and anyone who knows her that she is delusional. One of the chief ways he does this is to dim the gas lights in the house but insist to the wife, when she wonders why the lights dimmed, that they did not and she's seeing things.
It is unfortunate that this scenario is too often played out in our "real world." The abused wife whose husband undermines everything she says and does. The boss who tries to convince his staff that he did not say or do what he really did say or do. The political or religious leader who convinces followers that they are powerless.
With ready access to tools for communication and for assistance, it is more important than ever to speak up when someone is being gaslighted. It's time to be aware of and never lose sight of our individual power. I have been powerless, and in the past gave up my power out of learned habit. But no longer. Whether in a personal, professional or political situation, remember who you are. Remind others of who they are - powerful, creative, talented individuals. Leave gaslighting to the movies!