The great thing about being a monarchist, and in the military, is that I don‘t even need to expend a tenth of a second debating this topic in my head before I decide.
For me, it is just so clear and simple:
1. The Queen is the Sovereign and Head of State.
2. The Sovereign has sole authority to govern. Hence, they are "sovereign".
3. All government business is conducted in The Queen‘s name. This includes the authority to tax, to pass laws, to enforce laws, to judge laws and people, to declare war, to sue for peace, and anything else within a sovereign‘s prerogative (obviously many of these rights are necessarily conveyed to the representative government).
4. Thanks to the stability and tradition of nearly 1,000 years of constitutional monarchy, we have a system of government that best represents the rights of the majority and the rights of the minority; representative democracy within a framework of divine sovereignty, changeable by the will of the subjects because The Queen rules with the consent of the governed.
It may not have always been this way, but certainly the present head of state has done an admirable job of maintaining the dignity and status of the office without trivialising its role in a way only our elected officials seem to be capable of.
It is never a question of whether the sovereign‘s behaviour is beyond reproach. It is. Always.
And because of that, I am more than happy to fulfil my constitutional duty to my country to serve it‘s lawful and rightful head.
It is sad that some can quote the Queen‘s birthdate but can‘t soldier. Perhaps they should choose another calling, because they are probably not serving the Crown in their best capacity.
Certainly, however, one should endeavour to devote themselves to their duty, in whatever capacity it may be, military or not. If not for The Queen, then at least for benefit of their community, family and self.
I am reminded of the Queen‘s own devotion to her duty when she spoke at her Coronation Day speech, fifty years ago this summer, on June 6, 1953.
"I have behind me me not only the splendid tradition and annals of a thousand years, but the living strength and majesty of the Commonwealth and Empire, of societies old and new, of lands and races different in history and origins, but all by God‘s will united in spirit and in aim. Therefore, I am sure that this, my coronation is not the symbol of a power and splendor that is gone, but a declaration of the hopes of the future, and for the years I may by God‘s grace and mercy be given to reign and serve you as your Queen."
An aside:
My proudest moment thus far in my quite short military career was swearing the Oath before my CO. Even when I joined customs, we only signed a sheet of paper on which the oath was printed -- I felt a bit chitzed out, and technically the oath wasn‘t sworn before a commissioner of oaths and so it is of murky legality.