Stripping them of their wealth and exiling them would be debasing the rule of law in your country.
1. A new Royal Assent Act, that makes assent automatic upon a bill passing both Houses. Assuming this in itself receives assent, it would remove the monarch's power to veto or refuse a bill (a power that hasn't been used for over 300 years anyway).
2. A Republic Act, that transfers all powers, abolishes the monarchy, strips them of their wealth, exiles them, etc.
Where is the debasement here?
For instance, if parliament passed a law allowing “The Purge” to happen yearly, would murders committed on that day be “rule of law”? If you don’t think so, perhaps you agree there are some inherent principles to rule of law that aren’t simply a majority vote of a legislature. (For instance, perhaps there’s an assumption that exiling someone who hasn’t committed any crime is a violation of due process rights, rights as a citizen of the country, etc.)
While you could of course exile them like other countries have done in the past, why would you do that? What reasoning would you use to justify exiling them, striping them of their personal property etc. ?
Abolishing the monarchy is one thing, it can be justified pretty easily, the interests of the people. Anything beyond that however would be punishment, what have they done that is currently illegal that warrants that punishment? Punishing them simply "because they are royals" doesn't really work out, that isn't illegal after all.
Technically just abolishing the monarchy / taking away their powers would suffice.
> Technically just abolishing the monarchy / taking away their powers would suffice.
It wouldn't suffice, because they still derive a great deal of power from their inherited wealth. What's the point of abolishing the monarchy if we permit them to remain as landlords for huge swathes of the country? Then they're still lording it over people economically, even if no longer doing so constitutionally.
I am no fan of the royals and other nobles and look forward to the day when they all work for a living and wear seat belts like regular people. Yet, we must acknowledge that rule of law means law for the bad, the useless, and the rich. The ends don't justify the means.
This is not an intuitive concept by any means, but it helps to think about it in terms of the origins of the common law: the underlying idea is that the long acceptance of something or practice of something by regular people is a sound basis for its legitimacy. This still finds expression in the theory (in the US, anyways) that the speed limit should be the speed at which 85% of people drive. On this footing, the legitimacy of law is more about observation than about the decision of a particular person or administrative body.
Some things to contrast with the common law are "positive law" and "statute law". Legislation passed by Parliament is indeed statute law; it's not common law. Yet, to a significant degree, common law ideas and ways of judging remain prevalent in the United States, the United Kingdom and the other English speaking countries. It's the common law that defines most crimes with which you'd be familiar. It's more relevant than you think.
Although Parliament is indeed sovereign and Parliamentary sovereignty is said to mean that Parliament can not be bound even by Parliament, there are contemporary limits recognized to Parliament's law making authority. Sometimes they are even called "constitutional", referencing the unwritten English constitution; and sometimes they are clearly linked to the Convention on Human Rights. Either way, what we see here is an assertion of the old idea of "transcendent law" that binds everyone, even the law makers -- and that is what rule of law is really about.