Arms control is essentially a law-creating process at the international level. It refers to any tacit or explicit agreement among states aimed at reducing the likelihood of war, the costs of preparing for war, or the damage should war occur. Originally, it referred to any such agreement between prospective opponents (and assumed that friendly states would have no need for arms control), but this prerequisite element of potential hostility has long since passed as the concept has broadened in practice to include multinational agreements among groups of like-minded states.