|Abstract:||In OT with Candidate Chains (McCarthy 2007), candidates are multi-step derivations, and the PREC constraints which regulate the order of derivational steps can inspect entire candidate derivations. This means (Wilson 2006; Wolf 2008, 2010) that OT-CC opens the door to certain kinds of ‘global rules’ (Lakoff 1970) - that is, effects in which the application or non-application of a process is decided with crucial reference to derivational history. This paper investigates what limits may exist on OT-CC’s global-rule powers, focusing on three forms of opacity which are possible under a theory where all rules apply simultaneously, but not under sequential rule-application: mutual counterfeeding, self counterfeeding, and mutual counterbleeding. It is shown that the original version of OT-CC allows none, but that each of them could be made possible with relatively simple revisions to the original theory. Possible examples of these forms of opacity are discussed.