How do incumbents manage to relax term limits when they cannot impose their preferences unilaterally? Interpreting constitutional reforms as a bargaining game between a term-limited executive and the opposition, we argue that reforms involving term limits should be more likely when (a) the incumbent party can change the constitution unilaterally or (b) the opposition is pessimistic about its future electoral prospects. Moreover, (c) this second effect should be stronger when a single opposition party has veto power over a reform, because this precludes the executive from playing a “divide-and-rule” strategy. We examine these claims with data from the Argentine provinces between 1983 and 2013. Consistent with expectations, the results show that the probability of initiating a reform is highest when the executive’s party controls a supermajority of seats, but falls sharply when a single opposition party has veto power over a reform, and this party expects to do well in the next executive election.