Managing the nuclear complex across the vast expanse of the Soviet Union posed difficult challenges to the Soviet leadership. But by the combined use of several intersecting measures—strict controls over the movement of people, abundant physical protection in the form of fences and armed guards, and the ability of political police to arrest facility personnel and potential criminal perpetrators on the slightest suspicion—the Soviet Union effectively kept its nuclear energy and defense-related assets safe from would-be smugglers and terrorists. With the break-up of the Soviet Union, however, borders opened, many guards lost their wages and disappeared, fences fell into disrepair, and central funding for scientists collapsed. At the same time, an encouraging but unruly effort at democratization was transferring powers wholesale away from the center during the years of President Boris Yeltsin, despite gaps in the abilities of new, sub-national bodies to handle their new responsibilities. In the nuclear sector, these conditions led to serious problems by the early to mid-1990s, when financial reserves left over within the system from the Soviet era had been used up, critical staff had drifted away, and inappropriate regional actors (including criminal groups) had begun to step into the yawning gap in regional authority.