There is a strong empirical and historical case for thinking that the answer to this question is "yes." Injustice is a source of resentment, indignation, and conflict. In the long run, the victims of injustice will not be ignored. Justice is a security issue for states and supra-national organizations, and simple prudence demands that policy makers take it into account. To put a simple label on this idea, justice is a security issue.
Here is a European Union statement about its longterm interests that makes this point fairly explicitly (link):
In the context of ever-increasing globalisation, the internal and external aspects of security are inextricably linked. Flows of trade and investment, the development of technology and the spread of democracy have brought prosperity and freedom to many people, while others have perceived globalisation as a cause of frustration and injustice. In much of the developing world, poverty and diseases such as AIDS give rise to security concerns, and in many cases economic failure is linked to political problems and violent conflict. Security is a precondition for development. Competition for natural resources is likely to create further turbulence. Energy dependence is a special concern for Europe.What are the theoretical and historical arguments for this conclusion? Here are several.
On the side of theory, several points are well established. Chronic and unrelieved poverty leaves people with low attachment to their own societies and less for the global community. The frustration of very basic human needs is bound to fuel indignation and resistance. So poverty and deprivation are causes of resistance. But there is also evidence that inequality itself has negative consequences for a society's health; this is the central finding of The Spirit Level: Why Greater Equality Makes Societies Stronger (link). Finally, the social psychology created by a system that is perceived to be unfair and exploitative is likely to breed resistance and lawless action. Barrington Moore, Jr. was right when in Injustice he wrote:
Without strong moral feelings and indignation human beings will not act against the social order. In this sense moral convictions become an equally necessary element for changing the social order, along with alterations in the economic structure. 469Gareth Stedman-Jones summarizes Barrington Moore's conclusion in these terms: "His argument is that human beings in stratified societies accept hierarchies of authority, so long as these hierarchies are not merely imposed by force, but based upon an 'unwritten' social contract, which binds together dominant and subordinate groups in a set of mutual obligations" (link).
So there are good empirical reasons, based in social psychology and the study of contentious politics, for expecting that injustice breeds conflict.
Are there historical demonstrations of the consequences of injustice for disorder? There are. We have the examples of slave revolts throughout the Americas in the 18th and 19th centuries; anti-colonial movements in Africa and Asia following World War II; the sustained resistance of the Burmese and East Timor peoples to dictatorship; and the sustained struggle for equal rights in the United States by African Americans, sometimes punctuated by major urban riots. In each case a set of social institutions had been created that were profoundly unjust for a sizable population, and this population gathered resolve and courage in opposing those arrangements.
So the conclusion seems clear. If we want to have a world in which there is a sustainable level of the rule of law and a low level of social conflict, we need to invest in justice. We need to work to create a system in which all peoples can satisfy their most basic human needs; where everyone can feel that he/she is respected in her humanity; and where no one judges that the basic structure of social life is exploitative.
In other words, states are well advised to actively include the basic requirements of justice in their plans for the future. Otherwise they are simply creating the tinder for future conflict.