The League never became the universal organization that had been envisaged. Moreover, it failed to secure or retain the membership of certain major powers whose participation and cooperation were essential to make it an effective instrument for preserving the peace. Despite President Wilson's advocacy, the US did not join, and the USSR joined only in 1934, when the League had already shown itself unable to contain the aggressive policies of Germany, Italy, and Japan. The three aggressor states themselves withdrew their membership during the 1930s to pursue their expansionist aims. The UN, on the other hand, is approaching the goal of universality, with only a few smaller countries still unrepresented. By November 2002, its membership had reached 191.