In this paper, we explore a unified treatment of the difficulty of reaching a
decision in constrained distributed computing environments in which there is a
lack of global coordination or knowledge. We show a general impossibility
result for a broad class of decision protocols. Importantly, our impossibility
result holds, in particular, for "asynchronous, distributed, historyless
computation", in which each computational node's selection of actions only
depends on the current actions of other nodes, even under the assumption that
no node can be faulty.