The Nightwatchman

From Lastfm:

Tom Morello, guitarist for Rage Against the Machine, Audioslave and Street Sweeper Social Club, is less known for his folk music, which he plays under the alias "The Nightwatchman" as well as Tom Morello: The Nightwatchman which he used on his second album The Fabled City. He has explained, "The Nightwatchman is my political folk alter ego. I've been writing these songs and playing them at open mic nights with friends for some time. This is the first time I've toured with it. When I play open mic nights, it's announced as The Nightwatchman. There will be kids there who are fans of my electric guitar playing, and you see them there scratching their heads.

But it's something that I enjoy doing. I look at it more as an extension of my politics. Then again, some of the songs are not explicitly political. It really helped me grow as an artist and songwriter."

From Wikipedia:

The Nightwatchman is the alter-ego and solo act of Rage Against the Machine, Street Sweeper Social Club and former Audioslave guitarist Tom Morello. It was formed in 2003 as an outlet for his political views while he was playing apolitical music with Audioslave.