The Soviet Union made exporting revolution a high priority.
Although the USSR is gone, the effects of their subversion campaign linger to this day.
The script for Communist takeover
KGB defector Yuri Bezmenov gave an in-depth look.
[O]nly about fifteen percent of time, money and manpower is spent on espionage as such. The other eighty-five percent is a slow process which we call either ideological subversion or active measures, or psychological warfare.
He described how they recruited journalists and prominent figures to spread the Party line. Further, they compiled hit lists, including Communist sympathizers likely to outlive their usefulness after the Revolution.