I don't know if this counts as a song, but I wrote a sonnet in March of 2003 against Dubyah's war:

And so, against all sense, we go to war
How does this help the people, there or here?
We plunge whole populations into fear
Our leaders close the diplomatic door
Which leaves no chance for reason anymore
Shall we stand by and hope the air will clear?
Or simply pray that danger not come near?
Believing all will go on as before?

It is not true that ignorance is bliss
The flying bullet and the falling bomb
Care not if they kill soldier, child or mom
They bring to one and all death's icy kiss
Before it is too late, this war must cease
Instead of hate and anger, we need peace