All quiet on the revolution front

We've posed the question before, but today on the anniversary of the Kent State shootings it's time to ask again: What ever became of protest songs?

It has been 41 years since Allison Krause, Jeffrey Miller, Sandra Scheuer and William Schroeder were shot to death on the campus of Kent State by the Ohio National Guard -- the "tin soldiers" in Neil Young's raging "Ohio." The song, recorded by Crosby, Stills, Nash & Young almost immediately after the tragedy, has not lost a bit of its punch through the years. Even the video above from Young's 1971 Massey Hall acoustic performance resonates today, albeit in more reverential tones. It would be difficult to find a song with a more powerful opening line:

"Tin soldiers and Nixon coming..."

Abbie Hoffman once declared that "rock musicians are the real leaders of the revolution," and "Ohio" would seem to be his Exhibit A.  But where are the others to support such a notion?  Listeners who aren't paying close attention sometimes offer up Buffalo Springfield's "For What It's Worth," but Stephen Stills wrote that three years before Kent State. 

Maybe we just ran out of revolutions.