It’s already got a big fence on the south side. Just run it all the way around and make it like “Escape from New York”.
This is why voting matters. Crazies are motivated, eager to collaborate overlooking galling details, and have no shortage of confidence. Even if you don’t particularly like a candidate (one that’d make a detailed convincing promise to do something you support), there’s still damage control to be done weeding out the worst ones.
Put another way: Crazies will vote reliably; if you don’t, they win.
Of course this means primaries and local elections. They’ve gotta run their home state into the ground as a start.
* Bonus: Wikipedia says “[Amaterasu] is also said to be directly linked in lineage to the Imperial Household of Japan and the Emperor.”