What is the political message of this song, or what are they saying to the listeners? Do you believe it is an effective protest song?

Topic: Crosby, Stills, Nash and Young, ‘Ohio’
Watch and listen to the following music/videos and answer the questions below.

Crosby, Stills, Nash, and Young’s “Ohio” from Youtube Some background on how the song was written.
Crosby, Stills, Nash, and Young’s “Ohio” from Youtube Some background on how the song was written.
Questions
What is the political message of this song, or what are they saying to the listeners?
Do you believe it is an effective protest song?
What lyrics do you believe are the most powerful?