This song is about thoughtless devotion to a girl.  The speaker's situation could be interpreted as either favorable or not, as there is an argument to both.  But that's not really important.

"I wrapped you inside my coat when they came to firebomb the house.  I didn't feel pain, 'cause no one can touch me, now that I'm held in your spell."  This recalls a scene from George Orwell's 1984.  A ship is attacked, and a mother wraps her arms around her child who is being shot at.  It is a futile effort, as the mother's embrace would not keep the child from death.  Such is the nature of Thom's protection.  It is of no consequence at all, but it does carry meaning.  This verse also portrays Thom's feelings of invincibility, a supporting fact for an optimist's interpretation of the song.

"A beautiful girl can turn your world to dust."  At first glance, this line is dark in meaning.  It seems to say, "A beautiful girl can make everything suck."  But on another level, it could mean, "A beautiful girl can make nothing else matter."

"Sell me a car that runs.  Sell me a house that stands up."  This is a more negative lyric, not only suggesting a certain blindness in love, but also a willingness to accept anything that the girl offers.  However, Thom contradicts this mood with the repetition of the line, "I never cared before."  This adds a new depth to the second meaning of the chorus.  It suggests, "Yeah, I don't care about anything but her.  But before her I didn't care about anything but myself."

The last half-verse follows the same track the song started on.  "I stood in front of your face when the first bullet was shot."  Thom's love will not change anything, but it still exists, and that is real.