There have been many songs that support Liberal or Left-Wing side of Politics. Remember the left-wing includes Social Democrats, Socialists, Communists, and others as well as Liberals.

See also

Song Artist/Band Comments Year Genre
This Land is Your Land Woody Guthrie Has a pro-socialist message 1940 Folk
Imagine John Lennon Anti-War 1971 Rock
Revolution The Beatles Anti-war and anti-discrimination 1968 Rock
Banned in the U.S.A  2 Live Crew  Protested censorship  1990  Hip Hop 
Waiting on the World to Change John Mayer 2006 Rock
Give Peace a Chance  John Lennon  Anti-war  1969  Rock 
War  Edwin Starr  Says that war is good for "absolutely nothing"  1970  Funk 
Let's Impeach the President  Neil Young  Attacks George W. Bush and the Iraq War  2006  Rock 
Impeach the President  Immortal Technique  Calls for the impeachment of George W. Bush  2007  Rap 
One Tin Soldier  Dennis Lambert and Brian Potter  Vietnam War protest song  1969  Folk 
Same Love  Macklemore  Supports gay rights  2012  Hip Hop