Economic sanctions aim to exert pressure on a target nation or region to induce policy reforms or regime change. The effectiveness of sanctions depends on whether they inflict economic pain on the target (especially the targeted elite). This, in turn, depends on several factors. For trade sanctions, these factors include how readily a sanctioned nation can obtain substitutes for needed imports, the degree to which countries imposing sanctions rely on trade with a sanctioned partner, and the extent to which either side can rely on intermediary nations outside the sanctioning blockade to evade trade restrictions.