Politics and music have a long history. George M. Cohan wrote “Over There” in 1917. Neil Young’s “Ohio” was released in 1970 with the lyrics “Tin soldiers and Nixon coming.” Joan Baez was a protest-song factory between her 1967 “Saigon Bride” and 2017’s Trump-bashing “Nasty Man.” Bruce Springsteen performed at Obama campaign rallies. Lady Gaga and Jon Bon Jovi played his song “Living on a Prayer” before introducing Hillary Clinton days before Election Day in 2016. In retrospect, they were rather prophetic.