- US is about to have military on the streets during peacetime with no terror threat within a codified constitution
- UK has had military on the streets in response to terrorism in Northern Ireland (a real threat) and not for decades. The UK constitution is uncodified and spread over many (10+?) documents ranging from Magna Carta in the 1200s to the Bill of Rights in the 1600s to documents written in the 1800s and then more modern Acts of Parliament.
Importantly the UK constitution can slowly change which means the UK has never had a revolution and never will do. Whereas the US constitution is rigid which achieves the opposite: when it does change it'll be dramatic and as a result of another violent revolution.