A week into the struggle to defend the working families of Wisconsin from the assault on their rights by Governor Scott Walker and his Republican allies in the state legislature, a group of rockers from around the country showed up to sing in solidarity with the tens of thousands of Wisconsinites who had gathered outside the state Capitol in Madison.

Tom Morello, from Rage Against the Machine and Audioslave, Wayne Kramer from the MC5, Mike McColgan from the Dropkick Murphys and the Street Dogs, and a crowd of young rockers packed a union stage on a February 2011 day so frigid that the rockers when it joked about using their frozen fingers as guitar picks.

Yet they played their way through a rousing list of labor and protest songs.

The rockers finished with a song that everyone knew: Woody Guthrie’s “This Land Is Your Land.”

Born 100 years ago in Okemah, Oklahoma, Guthrie was a unapologetic and uncompromising union man who placed his voice in the service of many a strike during the rabble-rousing years of the 1930s and ’40s. And he wrote some of America’s finest labor songs. “Talking Merchant Marine,” Guthrie’s brilliant recollection of his World War II service on a Merchant Marine boat—where sailors were represented by the National Maritime Union—declared:

I belong to the union called the NMU I’m a union man from head to toe I’m USA and CIO Fighting out here on the waters to win some freedom on the land.

Of all Guthrie’s populist songs, however, “This Land Is Your Land” struck the deepest note. It was not just about the dignity of work. It was about the dignity of Americans and their right to expect more from their country than the same poverty, discrimination and neglect that he associated with the totalitarian states of Europe and the colonies of Africa and southern Asia.

“This Land is Your Land” has become a sort of people’s national anthem. In Wisconsin last year, it was restored to its radical roots, especially when rockers like Morello resurrected the “lost verses” that Guthrie sang when he wrote the song in the 1940s.

The original manuscript of “This Land is Your Land” was a call to action for economic and social justice:

Nobody living can ever stop me, As I go walking that freedom highway; Nobody living can ever make me turn back This land was made for you and me.

In the squares of the city, in the shadow of a steeple; By the relief office, I’d seen my people. As they stood there hungry, I stood there asking, Is this land made for you and me?

Morello would those words again and again through 2011 and 2012, as he appeared at union rallies around the world, as well as “Occupy” events. Bruce Springsteen would sing them; so, too, would Billy Bragg and others—including Pete Seeger and Guthrie’s son Arlo.

Woody Guthrie died too young, at age 55. If he were living, he would turn 100 on July 14.

It is remarkable that so many songs from this radical American’s musical canon are still sung.

It is even more remarkable, and reassuring, that the most famous of his songs is again being sung in the radical spirit that he intended.