An inteview with another live offer out!
Has anyone heard of such things happening? Getting a backup lined up outside of the first round of invites to campus interviews after an offer has already been put out?


It's not usual, but I have heard of such things here in Europe. And why not? If the search committee already knows that, or at least has the strong impression that, their originally preferred candidates are not going to work out, why not immediately line up backup interviews? I should also note that they seem to be playing with unusually open cards towards you, so I would certainly count this as a positive.

If I understand you correctly, your main problem seems to be that you already have an offer that you cannot delay until you will get a decision from this school. Note that it isn't only about whether the preferred candidate will work out or not - even if the preferred candidate cancels, you still need to ace your own interview and do better than the other backup candidates (typically, if a search commission goes through the trouble of inviting backup candidates, they will invite more than just one person!).

At the end of the day, your options are likely as follows:


Try to delay your standing offer, and/or convince the school where you are interviewing to hurry up. Some schools seem to be fairly flexible with timing (I have heard from TT offers to be delayed for many months), others are not. There is only one way to find out.
Cancel your standing offer, and take the risk with the interview.
Cancel your interview, and take the TT offer.
Accept your standing offer, go to the interview regardless, and back out of your earlier acceptance if you get the second job. You certainly can do that, but you should expect some backlash. I would not recommend that, even if it may appear like the approach with the highest short-term profit for you personally.


If you need to decide right now (option 2 or 3), you should ask yourself (a) how much better the second job is than the first one, and (b) how disastrous it would be for you if you ended up with no offer at all. Oftentimes, when making such decisions, it is better to take the offer that you already have than a slightly better offer that you may or may not get, but at the end of the day the decision is yours to make.