Should music ever be political? What about literature or other forms of art?

Of course music is political. Soldiers have sang together since the formation of militaries, just as every protest movement has had its fight songs and pleas for peace. Music is how people try to unite one another to a specific way of thinking; is there any application MORE obvious than politics?

Punk and folk obviously led this trend (interesting juxtaposition, no?) but political rock has also been the trademark of heavy hitters like Neil Young, Midnight Oil, Springsteen and U2.

Political statements are in all forms of art, from books to street graffiti. It's the only way to get people to think about it.

Have at it.