This is true, but neither can Brazil utilise their entire economy against him. Musk could definitely get a few billion out if he really tried (he got a $6b loan

This is true, but neither can Brazil utilise their entire economy against him. Musk could definitely get a few billion out if he really tried (he got a $6b loan backed by Tesla stock and $20 billion in cash to buy Twitter), and the equivalent of that amount back in the day would have been enough to finance a military expedition - the Boer War was at the modern day cost of 25 billion pounds.