Would the UK go to war if the monarchy was threatened by a foreign country?
It depends what you mean by the monarchy being threatened. It wouldn’t for just a threat against the Queen or Royal Family. That’s simply a criminal offence. Against the Queen herself or the heir to the throne, that is high treason according to the Treason Act 1351 (see link below). If the country as a whole is threatened, then of course it would go to war. There’s an interesting line in that Act which says that going to war against the monarch (effectively meaning the UK – as the head of state, the monarch is the personification of the country) is high treason, though it is difficult to see how you convict and punish a whole other country for it. The punishment when the Act was first enacted in 1351 was to be hanged, drawn and quartered (for men), or to be burned at the stake (for women). Over time that was reduced to death by hanging, until capital punishment was finally abolished in the UK in 1998 (it had already been abolished for murder in 1967, and the last executions took place
