Rolling Stones Told Trump Quit Using Our Song Back in May. It's playing now after Trump's speech:

[exboyfil]

8. Here is a Rolling Stones article about this

Basically by the time a court decision comes down, the election will be long over. The venue has the licensing rights to the song. The artist can complain, but it is a grey area.

http://www.rollingstone.com/politics/news/why-politicians-keep-using-songs-without-artists-permission-20150709

Technically speaking, copyright laws allow political candidates to use just about any song they want, as long as they're played at a stadium, arena or other venue that already has a public-performance license through a songwriters' association such as ASCAP or BMI. However, the law contains plenty of gray area. If a candidate refuses to stop using a song in this scenario, an artist may be able to protect his "right of publicity" – Springsteen's voice blaring over a loudspeaker is part of his image, and he has a right to protect his own image. "It's untested in the political realm," says Lawrence Iser, an intellectual-property lawyer who has represented the Beatles, Michael Jackson and many others. "Even if Donald Trump has the ASCAP right to use a Neil Young song, does Neil have the right to nevertheless go after him on right of publicity? I say he does."