Trump doesn't have to do anything.

Trump doesn't have to do anything. It's being done for and by people with much better deliberation and focus than he has. In fact, he's almost incidental. If one news organization has control over reaching 3/4 of US households, they will effectively function as a propaganda arm of the side they seem to be on. Right now, that side finds Trump useful.

http://www.pbs.org/newshour/bb/sinclair-broadcasting-puts-partisan-tilt-trusted-local-news/
http://www.pbs.org/newshour/bb/sinclair-broadcasting-puts-partisan-tilt-trusted-local-news/