The main problem with implementing such a radical tax would be finding acceptance. Although such a system might find acceptance within some nations, particularly those (1) with a history of neutrality, (2) without an active military (such as Costa Rica), or (3) with lower levels of military spending (such as Japan, which currently spends 1% of its GDP on defense), it would be unpopular among many consumers of arms. Nations in this latter category range from the United States, which spends 4% of its GDP on defense, to dictatorships who depend on arms to keep themselves in power. Other likely opponents would be nations engaged in ongoing military conflicts, or others in a state of heightened military alert, such as Israel. Arms producers would also oppose it, because it would increase their costs and possibly reduce their consumer base.