Abstract
<jats:title>Abstract</jats:title> <jats:p>This chapter examines how legal change unfolds within the increasingly complex institutional landscape of international law. It questions the common view that institutional complexity typically leads to friction or stagnation, arguing instead that multiplicity often facilitates change. Drawing on historical institutionalism, it contends that fragmentation across regimes and legal subfields can open opportunities for gradual, cumulative change, especially when actors sequence their actions across sites. To explain this dynamic, the chapter suggests that change agents often pursue ‘paths of least resistance’, strategically navigating fragmented regimes by selecting institutions—potentially peripheral ones at first—most receptive to their goals. Through cumulative authority-building across sites, actors gradually gain legitimacy for their norm change proposals, which also helps them increase the odds of success when later targeting more central institutions. Such paths increasingly lead actors to make ‘sideways moves’ between issue areas—such as from the trade to the human rights regime—to build authority in more receptive contexts to enhance the success of change across regimes. However, the chapter also acknowledges that not all such efforts succeed; change initiatives stall or lead to legal ambiguity when institutions diverge or resist convergence, and change agents often turn outside international law—to more flexible and receptive venues—to realize their goals. The chapter provides a rich account of how institutional complexity shapes international legal change, highlighting the interplay of strategic behaviour, regime fragmentation, and authority accumulation in the construction of new legal norms and understandings.</jats:p>