>>the purpose and character of your use
the nature of the copyrighted work
the amount and substantiality of the portion taken, and
the effect of the use upon the potential market

Right, and the first one is the one that bites. If use is not for research and education or criticism or parody, or (worse) if it's for commercial or promotional purposes- then you're going to struggle to assert fair use. Even if the link is tenuous as per the National Party example I gave earlier. Unauthorized playing of the unaltered song on National TV during a political moment is asking for it IMHO.

Whereas quoting a few lines of the chorus could be fair use, or if "Eye of the Tiger" had been parodied as "Eye of the Convert (with a beam in it)" then you'd have a really good shot of defending the claim.