What about the whole majority control thing? If another nation decides to scoop up a "controlling share" could they somehow gain control of the ledger? Could that be part of the reasoning in any way?
TLDR: They could, but it'd be difficult and might require things like creating a national botnet or knocking other people offline.
How this works depends on "proof of work" versus "proof of stake" systems. Bitcoin is the former, where that kind of takeover requires controlling the majority of computing-power being actively used to confirm transactions.
Imagine a branching tree growing upwards, where every node is "and then this transaction happened next." Everyone has already agreed to treat the longest total path as "the true one". This leads to a tree which is very very tall with lots of short dead stubs for transactions that had to be retried.
People assume their transaction is safe when it is embedded far enough back that it looks like it'll always be on any longest path going forward. By controlling a majority of the computing power, you can create your own branch of events and ensure it will be longest, even if everybody else is making a deliberate effort to say "no, these other transactions happened instead."