Trump’s Tweets Are A Master Class In Psychological Projection

Psychological projection entails subconsciously denying one's own qualities and attributing them to others instead.

Here, prior to becoming President, Trump calls President Barack Obama, the most dishonest President in ‘history’. Trump still behaves as if President Obama’s tenure in the White House was full of scandal and impropriety. It wasn’t.

Via Wikipedia:

“Psychological projection is a theory in psychology in which humans defend themselves against their own unconscious impulses or qualities (both positive and negative) by denying their existence in themselves while attributing them to others.”