In the last dozen or so years of the Roman Empire, the people just mentally checked out from the government. They stopped voting (when allowed and the few who could), stopped joining the military, stopped being involved in any level of community or civics. As a result, the government imported "the barbarians" to be in the military and shitskins to run the day to day of the government. Think affirmative action laws and importing non-whites to join the army and be cops. History just keeps repeating itself.