My nominee for best would be Shipbuilding as done by Elvis Costello or Robert Wyatt.
My nominee for worst would be The Luck Of The Irish by John Lennon with Yoko Ono.
Definitions, please. Best tune? Worst lyrics? Do you have to agree with the stance of the composer? C’mon…a little help here.
Provisionally ( 
), let me offer
Best: “Come Out Ye Black and Tans” - Dominic Behan
With so much hostility toward many aspects of the governement, I have always found a sort of solace in Rage Against the Machine.
Favorite song: Sleep Now in the Fire
Least favorite: Anything by Shenade O’Conner
Without too much thought applied … among the best are Stevie Wonder’s “You Haven’t Done Nothin’” and The Pretenders’ “My City Was Gone” (and no, not because of the Rush Limbaugh connection )
Well, while it didn’t help Walter O’Brian much, the MTA song is catchy and became famous by the Kingston Trio.
You just reminded me Sinead O’Connor’s Famine is one of the most unintentionally most hilarious songs ever written.
Another good one is Peter Gabriel’s “Games Without Frontiers”.
Best: “Political Science” by Randy Newman
I won’t say it’s the best, but I like Rush’s “Trees”.
I will say the worst AND most overrated is John Lennon’s (yes, I’m ready for the pile-on) “Imagine”. Musically, it’s beautiful. Lyrically- bleh!
This Johnny Cash song has always been one of my favorites (though it actually deals more with the danger of infusing music with politics, albeit in a playful and humorous way). 
No Surrender?
Only joking 
I agree with the sentiments (at least the polite lyrics) but the song became so distorted that it’s effectively unusable. Also musically it’s shit.
I’m quite a fan of “The times they are changing” or “The fletcher memorial home”… and who can forget “Ghost Town”… or “Anarchy in the UK”.
I love all of those despite not agreeing with any of them especially.
Do they have to be modern songs? A helluva lot of traditional Irish and Scottish songs were political back in the day. “Loch Lomond” and “The Wearing of the Green” are only two examples. “The Skye Boat Song” may have the sweetest tune of any political song ever.
Three currently residing on my Ipod:
Phil Ochs’ “Love Me, I’m A Liberal”
Bill Horwitz - “If I Had A Friend Like Miss Rosemary Woods” (the best Watergate-themed song)
The Fugs - “C.I.A Man”
I suppose it was inevitable that someday I would agree with Friar Ted on something. “Embarassingly pretentious trash” would be overgenerous praise for “Imagine”. Even the music sounds like something a precocious third-grader might write.
I have always (I say this, but they’re both relatively new songs) Bright Eyes - When the President Talks to God and Cursive - 10 Percent to the 10 Percent
You picked “The Trees” and you’re complaining about dumb lyrics?
My favorites: “Divide And Conquer” by Husker Du, “Revolution” by The Beatles
Least favorite: “What’s Going On?” by 4 Non Blondes and “Masters Of War” by Dylan (actually, anything by early Dylan - it’s all too friggin’ obvious IMHO)
Stephen Stills’ “For What It’s Worth” is one of the top songs of the 60s. Although he later converted it to an attack on Vietnam, it was written about the so-called Sunset Strip riots which were to keep clubs open. That’s why it has the most perfect, cynical observation about protests ever written:
Steppenwolf’s “Monster” is off an angry political album of the same name. Even for the time, it was too angry and political to be a hit, but it’s an unjustly neglected album.
For all purpose the-world-is-going-to-hell political purposes, though, there’s nothing that beats Leonard Cohen’s “The Future.”
“Revolution #9” has to be on any worst list. Even if the list has nothing to do with music.
Nixon’s the one
Nixon’s the one
Nixon’s the only one
We believe in Nixon
N-I-X-O-N
Nixon’s the only one.
Recorded for the 1972 presidential campaign. The only campaign song that could be agreed upon by both supporters and opponents (“Nixon’s the one, all right.”)
Speaking of Nixon, Neil Young’s Ohio is quite a good one.
Won’t Get Fooled Again – The Who
Eve of Destruction – Barry McGuire
We Didn’t Start the Fire – Billy Joel
IMF Lullabye – Tom Lehrer
I don’t 100% agree with all the songs on this list, but they do rock.
Peter Gabriel, Biko
U2, Bullet The Blue Sky
Midnight Oil, Beds Are Burning
Crosby Stills Nash & Young, Ohio
Neil Young, (Keep On) Rockin’ In The Free World
Kinks, Catch Me Now I’m Falling
KRS One, Sound Of Da Police
Public Enemy, Fight The Power
Tracy Chapman, (Talkin’ 'Bout A) Revolution