From Vanity Fair: “According to several people briefed on the discussions, the presumptive Republican nominee is examining the opportunity presented by the ‘audience’ currently supporting him.”
So imagine a Trump television network and Internet multimedia operation in the wake of a Democratic victory in November. It would, of course, have to out-Fox Fox. It would be dedicated to telling the most dedicated supporters of the presumptive GOP nominee what they want to hear. 24-7 coverage of the themes Fat Crybaby is currently hitting on the stump.
How much damage could that do? The case for “none” is that there will be a backlash to Trumpist nativism after the election; moreover, Fox has already mined those veins for all that they are worth. (Viz its coverage of the New Black Panther Party.)
The case for “a little” is similar, just assuming that the new venture could move the Overton Window a little bit and might push Fox to become even less hinged.
The case for “a grave amount” is that it would provide a platform for extreme nativism and abet the creation of large-scale organizations openly dedicated to white identity politics. The Overton Window moves somewhere out to geosynchronous orbit.
I have no idea.