Temporary teams can accomplish tightly-coupled complex work without the enabling conditions that support coordination in traditional teams. To advance understanding of this process, I conducted an inductive study of temporary teams in four hospital emergency departments (EDs), and found effective team coordination in two EDs, but not the other two. To theorize an explanation, I draw on organizational justice literature and introduce the idea of justice enforceability, defined as individuals' perceptions of whether authorities can act fairly, given the potential for other people to cheat. The team members' perceptions of justice enforceability were focused on whether the distribution of work within and between teams was fair or could be cheated. Justice enforceability mattered for coordination because it predicted whether teammates felt unity of commitment to their interdependent work and were therefore willing to engage in the extra-role behaviors that coordinated their efforts, or whether they felt self-protective and avoided the extra-role behaviors that would have made them suckers for working hard while others cheated. Justice enforceability thus resolves a tension for temporary teams: the potential for cheating under equitable workloads undermined extra-role behaviors and coordination, but an exactly equal distribution facilitated coordination by enforcing they were all "in it together."