From Ammoland:

In 1984 ex-KGB officer and Soviet defector Yuri Bezmenov taught us about the Marxist plan for what they called ideological subversion. The term is foreign to most Americans. In a nutshell, it is the slow process of changing the perception of reality of Americans when it comes to the right to defend themselves, their community, their family, and their country. The communist laid out their diabolical plan in four phases.