This hypothetical is so far from the 2000 election as to be unrecognisable. If I'd written "If Nader takes enough votes from Bush..." it would be about as realistic.
In any case, if Gore preferences flow to Bush over Nader, that's because those voters are expressing their preference for Bush over Nader. That's not spoiling: it's literally the entire point of providing a full ranking, is so that nobody's vote is ever discarded and so that any winning candidate must have accumulated an absolute majority.
> a third-party candidate doesn't spoil an election, because your second-place vote will still count. (E.g. Nader wouldn't have taken votes from Gore, so Gore would have won instead of Bush.)
I was just trying to point out that this isn't always true. Instant Runoff Voting can eliminate the centrist, the best compromise candidate, first.
If we adopt IRV and third-parties grow, then we move into territory where IRV gets some elections obviously wrong. It has happened.
In any case, if Gore preferences flow to Bush over Nader, that's because those voters are expressing their preference for Bush over Nader. That's not spoiling: it's literally the entire point of providing a full ranking, is so that nobody's vote is ever discarded and so that any winning candidate must have accumulated an absolute majority.