What makes a great politcal or protest song?

What makes a great political or protest song? The best definition of leadership is whether or not people follow, and the same is a good standard for judging political songs as well. If it moves people, or otherwise has an impact, it's a a success. The 60s protest songs truly helped end the war and Neil young's "Cortez the Killer" was banned for years in Spain (making it an underground hit).
But I want to concentrate on the music a bit more. Here's my criteria: 1. It must be a good song in and of its self. If you change the lyrics to "ode to a peanut butter sandwich" it would still sound good. 2. The lyrics have to be clever and bring an interesting take to the issue. There were a ton of very boring "Bush sucks" or "Bush is dangerous" or "Bush is an idiot" songs during the W years. Have a take, please. 3. The best political songs paint a picture or tell a story and 4. add a personal touch. The best songs add a personal element that pull you in on an emotional level. When Neil Young sings "What if you knew her and found her dead on the ground" about the Kent State Massacre in "Ohio" you truly feel like you're there. In fact, Neil is one of the greatest political/protest song writers ever because most of his songs in this genre use brilliant narratives that really hit home.
I make a slight distinction between "political" and "protest" songs. A "protest" song does all the things a "political" song does, but has the additional quality of being physically moving. They make you want to stand up and sing, and march and act!. Like Country Joe's "It's one, two, three, what are we fighting for?" or the Clash's "These are your rights!" Imagine being one of a couple thousand people singing aloud "You can get anything you want at Alice's Restaurant" or trying to stay in your seat as Bob Marley sings, "Get up! Stand up! Stand up for your rights!" "Strange fruit" is an incredible political song, while "This land is your land" is one of the best protest songs ever (though it seems to have lost it's teeth over the years).