As communism collapsed, disagreements emerged that endured until 2014. Russia struggled unsuccessfully to keep Ukraine in a new Moscow-led union and disagreement over the Black Sea Fleet and its base in Crimea proved unresolvable. Meanwhile, Russia and the West advanced different visions for post-Cold War Europe. Pressured by both Russia and the United States, Ukraine agreed to surrender its nuclear weapons in return for security assurances. Already in 1993, the prospect that a “red-brown” coalition of communists and fascists would come to power in Moscow prompted many countries to look for ways to guard against Russian reassertion, exacerbating the security dilemma.