U2's music—especially the Edge's soaring guitars—supports this lyrical vagueness. Their songs are gorgeous and majestic, but they produce only a single (though wonderful) emotion: a kind of lovely swelling of the soul. (For a sample of this in its purest form, listen to this snatch of "I Still Haven't Found What I'm Looking For.")
This is the U2 paradox. Bono and Co. are constantly dedicating songs to specific causes, exhorting their fans to think and act in the world. Yet their music does exactly the opposite of what it intends. Politics is the process of channeling the heart into thought and action. U2's music declares that the heart is all that matters.