"Not getting it quite right" is an understatement. The left-wing loonies basically created a power vacuum that they were not prepared to step in and immediately fill. Power abhors a vacuum, so of course someone will fill it, and it happened to be the left-wing loonies' enemies. But the odds were pretty good it would be somebody they didn't approve of, so what exactly did they accomplish, except murdering millions of people?
If they didn't have a power infrastructure set up and ready to go - which would require thousands of people to actually be in on at least part of the scheme, because you can't weild power with just five people in your gang - their scheme was always doomed to failure and if they had half a brain, they should have foreseen that.
Removing a corrupt power structure just to create a vacuum that will inevitably be quickly filled by another corrupt power structure (duh!) is not my idea of a brilliant plan. I know Hollywood writers have a reputation for being out of touch with the reality of how things work, but anyone should have been able to predict that result, even if they aren't any kind of DC insider or power-monger.
Just try reading a few history books. Sudden violent vacuums of power generally lead to very bad things as the vacuum is filled by god only knows who, because the unsavory types are precisely the ones who are primed to take advantage of power vacuums, and the most ruthless will elbow their way to the top. It's happened many times in history, but I can't think of one example of a conspiracy this stupid ever happening in real life, and considering how stupid humans can be, that's a pretty amazing accomplishment.