International efforts to reduce levels of violence among states and between people are based upon the drafting of international treaties and the creation of institutions empowered to enforce them. Hampering efforts to curb the destructive behaviour of states is the sovereignty of the modern state, which makes international law consensual rather than obligatory. In the absence of a world government with the capacity to limit the actions of states, the system relies largely on either the self-restraint of states or the collective action of nation-states through international institutions.
While it is very difficult to project into the future the likely success of international laws and institutions in their efforts to promote a more harmonious and less destructive international system, a few observations can be made with some degree of confidence. Regarding human rights, it is clear that the momentum that led to the drafting of scores of important human rights documents since 1945 has not abated. Public interest in the protection of human life and individual liberties remains extraordinarily high and, it seems certain, will lead to even more human rights treaties. Further, the immunity traditionally reserved for heads of state, such as presidents or prime ministers, is less applicable as human rights treaties increasingly erode it. The crime of aggression, i.e. authorizing an illegal war, exposes heads of state to prosecution by a foreign or international court, and the Convention Against Torture (CAT) explicitly rejects head of state immunity. As such, not only can we anticipate that further advances will be made in developing more human rights provisions, but also the capacity to hold violators accountable is increasing.
In terms of the laws of war, the trend lines appear to be negative. Since the end of the Cold War, certain powerful states have indicated an increased willingness to go to war without legal authority. The United States used military force in Bosnia in 1995, waged an extensive aerial bombardment campaign in Serbia in 1999 and invaded Iraq in 2003, all without invoking self-defence or obtaining Security Council authorization. In 2008, Russia invaded Georgia and in 2014 annexed Crimea from Ukraine, also without pretext or authorization. Members of the North Atlantic Treaty Organization (NATO) expanded upon a Security Council resolution in 2011 that authorized a no-fly zone over Libya to justify a six-month aerial bombing campaign that toppled the Ghaddafi government.
Actions by the major powers can have a sustained impact on the rest of the international community. The willingness of certain powers to use force with little reservation is an indication that the legal prohibition on the use of force may be weakening.