West Virginia seceded from a state that seceded (Virginia), so those were kinda special circumstances.
As for the Dakotas & Carolinas, those both entered the US as separate states AFAIK, rather than separating after they were in the US.
As for the Dakotas & Carolinas, those both entered the US as separate states AFAIK, rather than separating after they were in the US.
Disclosure: I have no clue about the underlying political/"cultural" differences of Idaho in contrast to the rest of the states...or Florida for this matter.
In practice, though, would the 49 remaining states invade Idaho & force them back in? The middle of the state is pretty wild & mountainous.