Blockades have been used primarily as wartime measures to reduce the military power of foes, and they have been employed by both sides of the conflict to seek an advantage. During the conflict, blockades tend to become more inclusive in terms of the definition of contraband, including attempts to limit foodstuffs in order to weaken civilian consumption. Nevertheless, their success rate does not seem very high, because of difficulties of enforcement, the willingness of neutrals to trade with belligerents, and the difficulties when land access to one of the belligerents would be possible. Military strength and productive capacity play a more important role in the outcome of war, and the blockade will end when the war is over.

More recently, blockades have been deployed in an attempt to substitute for war, to attempt to coerce certain nations to meet the behavioral requirements of other nations or groups of nations. Such peacetime, or Pacific, blockades, tended to be imposed by strong nations against weaker nations, and they tend to be more limited in the definition of contraband. Such blockades have ceased either when success was achieved, or when the imposing nations feel that little further is to be gained by continuing. These blockades, too, have not been overly successful, as trade with nations not involved in blockading often continues, and world public opinion may limit the effectiveness of the blockade because of the adverse impacts on the population.