802. This Land Is Your Land by Woody Guthrie (1944)

Guthrie got sick of hearing Kate Smith's version of Irving Berlin's "God Bless America" on the radio. He felt the song disingenuous and decided to write a song he felt better reflected America. Guthrie sometimes changed the verses based on his mood. Some of the lyrics were overtly leftist and he modified them as he felt appropriate. Over time, the song has lost its overt political connotations.

http://www.youtube.com/watch?v=wxiMrvDbq3s

Kate Smith's "God Bless America":

http://www.youtube.com/watch?v=pCavKL2zdjM