> Contrast between literal statement and underlying meaning
> Incongruity between what might be expected and what actually occurs
Actually, the latter does. Your original response--something to the effect of, "The song can't be about loyalty because the narrator diddles the woman"--shows us why: you wouldn't expect that an adulterer's loyalty (as opposed to lack thereof) would lead to his doom, and yet in the song (at least on my reading, and Justin's) it does.
> I had an English lit prof (Richard Poirier) who gave a lecture
> once about how "irony" was a common substitute for failure
> to engage the text.
Perhaps, but it's rather difficult to clearly and completely engage a text that centrally employs irony without using the term "irony" at some point (at least if you're writing in English--though I suppose most would catch on if you used the German "ironie").
-- Luke