Mental health professionals have made much of the practice [of gaslighting], said to be a favorite of narcissists and abusive spouses. But more recently the tactical tampering with the truth has become a preferred method of strongmen around the world. Gaslighting by other means was always a common feature of dictatorships, but it has found new vogue as a more subtle form of domestic political control even in countries with varying degrees of democracy. Now Trump has brought it to the United States. The techniques include saying and doing things and then denying it, blaming others for misunderstanding, disparaging their concerns as oversensitivity, claiming outrageous statements were jokes or misunderstandings, and other forms of twilighting the truth.
-- Frida Ghitis, "Donald Trump is 'gaslighting' all of us"