Enemies from within

In the course of human history, there were periods when a powerful country ruled the world. Eventually, every one of them lost their power to rule, and not necessarily losing a war to another power, but rather from "enemies within." In every case it has been the enemies within the country that completed the coup. Now the enemies from within could be for good or evil. It seems to be that we are already in this process, although you may disagree. I mentioned before that it is a Marxist-Communist