You wrote, "The college policy is that all tenured professors (including both associate professors and full professors) sit on the college-level committee to review new tenure cases. However, for at least the last several years, associate professors have not been included on the committee."

Did you truly mean that "all tenured profs sit on the college-level committee" or perhaps that "all tenured profs are eligible to sit on the college-level committee?"

You mentioned that your fiance is at a private school, so it could be small enough that the former is the case. But that's (in general) a lot of profs to have on a committee. Typically the college-level committees are only made up of representatives from each department. (For example, the college-level committee in engineering at VT has two reps from each department. The department head and another tenured prof that is elected from each department). Most college-level committees do not include Associate Profs because they are not eligible to pass judgement on other Associate Profs that are up for promotion to full Prof (but maybe her university has separate committees for that?).

Best of luck to you both. That's rough when a college-level committee goes against a departmental committee.

For what it's worth, my college (engineering) at VT is being sued by a prof that was denied tenure recently (though, his case is quite flimsy).