Where have all the protest songs gone?

It was a Wednesday in August 1963. Melody and electricity were commingling in the breeze as a quarter of a million Americans sang along with Joan Baez on the Mall.

We shall overcome, someday.

After that came Bob Dylan, Odetta, Peter, Paul and Mary, Marian Anderson, Josh White and the SNCC Freedom Singers, all raising their voices against racial injustice at the March on Washington.

While the Rev. Martin Luther King Jr.’s words changed history that afternoon, the songs surrounding it epitomized a decade of politically charged pop music that gave a soundtrack to the civil rights movement and rebuked the war in Vietnam.

But nearly a half-century later -- with unpopular wars quietly raging overseas and end-times economic panic blaring at home -- protest songs seem to have lost their power, potency and appeal. How did this happen?

It’s a long, slow fade that British author Dorian Lynskey tracks in his recent book “33 Revolutions Per Minute: A History of Protest Songs, From Billie Holiday to Green Day.” Chapter by chapter -- 33 in all -- Lynskey examines the work of Nina Simone, Gil Scott-Heron, the Clash, Bruce Springsteen and others who made fire at the intersection of music and activism.

But in the tome’s epilogue, the author wonders if he’s actually written a eulogy for the protest song. “If it is a eulogy, it’s a eulogy for the idea of the mainstream protest song,” Lynskey says over the phone from London, “the undeniable mainstream protest song which soundtracks certain events and maybe even changes people’s minds.”

Somehow, mind-changing, mainstream protest songs don’t seem to have survived into the 21st century. But those who say protest music itself is dead may not be paying very close attention.

“They aren’t listening,” says Tom Morello, former guitarist of Rage Against the Machine. “There may have been more unity around a song like ‘We Shall Overcome’ at the height of the civil rights movement, there may not be that one global, unifying anthem, but certainly there are strands of protest music now that are a vital part of today’s fight for justice.”

On Tuesday, Morello will release his second solo album of protest songs under the name the Nightwatchman, making him one of countless contemporary artists meshing music with protest. But he’s peddling it to an America that’s grown dubious of superstar musicians flexing their political muscles -- or lack thereof.

During George W. Bush’s presidency, the outrage of our rock stars consistently failed to register in our earbuds. Neil Young, Radiohead, Erykah Badu, Pearl Jam, R.E.M., Bright Eyes, Pink, the Beastie Boys and many others wrote well-publicized songs opposing Bush’s policies and the war in Iraq.

But ask someone on the street to try to hum one.

Public Enemy’s definitive 1989 hit “Fight the Power” might have been the last great, galvanizing American protest song. Sonically innovative and lyrically trenchant, it arrived at the end of a decade when musical activism felt more like celebrity do-gooding. “We Are the World” and Farm-Aid were noble causes, no doubt, but they fostered a certain distrust of artists who were seen as merely burnishing pious images.

The chain is broken?

Twenty-five years earlier, protest singers still had America’s trust. “With the possible exception of Peter, Paul and Mary, they really were not making money of out of this,” says Dick Weissman, author of “Talking ‘Bout a Revolution: Music and Social Change in America.” “But when you’re making hit records singing about revolution, you kind of get to the absurdity of Mick Jagger singing ‘Street Fighting Man.’ I mean, Mick Jagger has probably never been in a street fight in his entire life.”

When “Fight the Power” was released, Public Enemy wasn’t a group of stars who had suddenly developed a political stance; it was a group with a political stance that made the members stars. And they were part of a lineage.

“The tradition of writing protest songs was handed down informally,” says Lynskey. “If you were of Dylan’s generation, you could look back to Woody Guthrie and Pete Seeger. If you were a punk, you could look back to the angrier records of the late ‘60s, as Joe Strummer did. If you were a rapper like Chuck D, you could look back to James Brown and Curtis Mayfield.” But after Public Enemy, Lynskey says, “that chain kind of stops.”