  This idea comes in various versions. One idea is that it makes sense to deploy the concept of justice—not just egalitarian justice, but any justice notion—only where there is a stable scheme of enforcement in place, or at least the potential for that, which only the framework of a functioning state supplies (Nagel 2005; for criticism see Cohen and Sabel 2006 and Julius 2006). The basic thought is that justice norms cease to be binding if the individual cannot be confident that others will comply so that the goods the scheme of justice promises will in fact obtain. If a bus is stalled at the bottom of a hill, and the passengers can work together to push it to the top of the hill if all cooperate together, but pushing by less than all produces no gain, and there is no expectation that all the rest will cooperate, one has no clear duty to cooperate by doing one's “fair share” of pushing. But the bus example is a special case, which may not generalize to illuminate the run of global justice issues. If some of us insist that the products we buy not be produced by coerced or maltreated laborers, and the result of the insistence is that some laborers suffer less coercion and maltreatment, whether consumers generally follow our example may not diminish or offset the effects of what some do. Justice might require me to join the some who are insisting on fair play. If there is a justice duty falling on economically advanced nations to open their doors more than they now do to needy would-be immigrants, one country's opening its doors as required by this duty does good for the people admitted independently of whether or not any other advanced nations follow suit. My behaving in a way that emits excessive greenhouse gases may result in harm in the future to some determinate persons that is caused by me and would not occur but for my actions, and these facts may bring into play a duty of justice to refrain from wrongfully harming non-consenting others.