The artist has no choice. If Trump pays the mechanicals to ASCAP or BMI, he can use the music. Public performance is a compulsory license.
Yes and if I were Trump I would not stop using the song. His buddy will get over it after the election. He’s probably catching a lot of heat from other performers or he wouldn’t say anything.
I think Rush Limbaugh had a problem like this, and he was able to use the music in spite of the artist's objections.
No, as I understand it for public performances you must gain permission. For ex,, my film company was not permitted to use “Voodoo Child” by Hendrix in our movie, even if we paid. The performance rights must be granted and can be restricted.