Austria began to reassess its definition of neutrality following the fall of the Soviet Union, granting overflight rights for the UN-sanctioned action against Iraq in 1991, and since 1995, it has developed participation in the EU's Common Foreign and Security Policy. Also in 1995, it joined NATO's Partnership for Peace (although it was careful to do so only after Russia joined) and subsequently participated in peacekeeping missions in Bosnia. Meanwhile, the only part of the Constitutional Law on Neutrality of 1955 still fully valid is to not allow foreign military bases in Austria. Austria signed the UN's Nuclear Weapon Ban Treaty, which was opposed by all NATO members.