I think you have it backwards - Music is influenced by political leaning. Case in point: i like country music because it re-enforces things I hold dear: Freedom, guns, Hot chicks, A few beers, Family, and kickin-ass.
I like R&B because it re-enforces OTHER things I hold dear: Sweet, sweet lovin', good times with my signifigant (but impure, according to Gabby) other, dancin', and what-not.
I like some grunge and rap, though - because it's just good music. When I'm in a grunge mode, I take a few days between showers, wear flannel, and veg-out. When I'm into Rap it's a sunny friday and I'm on the way home from work with my car stereo volume set on "30" causing my car to sound like it's got empty cans in the trunk. (need dynamat).
etc..
Liberals like whatever music re-enforces their ideas of thought-control, statism, communism, and hate for the poor. Often those songs span many genres, however.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.