If the Justice Department can find another way to place insurrectionist violence in a compelling narrative framework, that is preferable to proceeding under RICO — i.e., you get the prosecutorial upside without injecting all of RICO’s complexities into a scenario that is not what RICO was designed for (not least, its extensive and, in parts, abstruse jury instructions).
This is why we ended up charging our terrorist defendants with seditious conspiracy. As already explained, prosecutors are drawn to RICO because the enterprise is broader criminal arrangement than a traditional conspiracy to commit a specific crime. A broad scope makes more incriminating evidence admissible, and more incriminating evidence increases the chances that defendants will be convicted. While a seditious conspiracy is not quite a RICO enterprise, it is an unusually broad agreement, covering everything from levying war against the United States, to opposing the government by force, to forcibly hindering the execution of the law or seizing the government’s property.
Conspiring to levy war and violently attack a superpower are not like planning to knock over a convenience store. A serious levy-war scenario involves many people carrying out an array of activities. These may not be quite as wide-ranging and obviously sinister as a RICO enterprise’s activities, but they’ll be sufficiently extensive and purposeful to show that conspirators contemplate projecting force on a significant scale: training and recruitment of fighters; acquisition of defensive gear, explosive components, and firearms; surveillance of targets; and so on. Like anti-American rhetoric, such conduct is not necessarily criminal on its face, but is of the kind that a violent uprising against the government would be impossible without.