I can't find anything in DT on this song, and Google's no help, either. It's clearly referring to a specific incident in Spanish Harlem, and given the timing, I'm sure that the song is an example of Ochs as a singing newspaper. Does anyone know anything further about the story of Lou Marsh? All I get from searching online is some canadian hockey player.

Lyrics follow:

LOU MARSH
(Phil Ochs)

On the streets of New York city when the hour was getting late
There were young men armed with knives and guns, young men armed with hate
And Lou Marsh stepped between them and died there in his tracks
For one man is no army when the city turns its back

CHORUS
Now the streets are empty, now the streets are dark
So keep an eye on shadows and never pass the park
For the city is a jungle when the law is out of sight
And death lurks in El Barrio with the orphans of the night

He left behind a chamber of a church he served so long
For he learned the prayers of distant men will never right the wrongs
His church became an alley and his pulpit was the street
He made his congregation from the boys he used to meet
CHORUS

There were two gangs approaching in Spanish Harlem town
The smell of blood was in the air, the challenge was laid down
He felt their blinding hatred, and he tried to save their lives
And the answer that they gave him was their fists and feet and knives
CHORUS

Will Lou Marsh lie forgotten in his cold and silent grave?
Will his memory still linger on, in those he tried to save?
And all of us who knew him will now and then recall
And shed a tear on poverty, tombstone of us all
CHORUS

If this is really the only easy to find version of the story, I think this is a fascinating example of how people can be remembered primarily through art.