Two post-tenure review (PTR) proposals are headed towards UK and it's important not to confuse them. The first is a bill prefiled in the Kentucky legislature, by Senator Tim Philpot. It is what is unfortunately on the verge of becoming the "standard" for those states that have begun meddling with academic freedom by legislative fiat: all faculty are reviewed every five years, with the emphasis on sacking those who don't measure up.
The second PTR proposal is from the UK Senate Council probably suggesting that UK adopt campus-wide the system now in effect in the College of A&S. Only those A&S faculty judged by the merit evaluations to be doing a truly miserable job (D+ over a 4 year period on a significant part of their work) are selected for evaluation; the emphasis of the A&S system is on faculty re-engagement and development; and there are lots of safeguards and appeals. The A&S PTR system itself was supported by the UK AAUP Chapter Executive Committee in 1994 and voted in on a trial basis by the A&S faculty by a large margin.
Pretty clearly, it is the bill in the legislature that we should be worried about. Please examine Senator Philpot's Proposed PTR Legislation and Senator Philpot's Press Release.