Empires have fallen before. The British, French, and Portuguese empires all fell in the second-half of the 20th century. Our “global ruleset for processing politically bankrupt empires” has been to encourage the center of the old empire to act as a responsible country, and forget its imperial ambitions. So we purposefully went out of our way to encourage Britain, France, and Portugal to lose their imperial positions. This process was occasionally painful, for instance during the Suez Crisis which caused the collapse of the British government. However, because the center of the old empire was esentially “Core” in nature, the process was eventually successful.
When the Soviet Empire fell, the same “global ruleset for processing politically bankrupt empires” was run on Russia. This encouraged the center of the old Soviet Empire to act responsibly, while encouraging Russia to forget its old empire. This process was occasionally painful, for instance during the Kosovo War, when their client lost some territory. However, because Russia was essentially “Gap” in its nature the process failed, and we are left with a belligerent successor state — an angry version of Portugal after her empire.