That's an interesting question... should royalty be allowed to stand for political office?
I'm inclined to think "Why the hell not?"
If someone, royal or not, is going to play the political game, they have to earn their victory. They have to convince the voters. And they have to deliver if they want to stay there. Just like anyone else.
In a world where (groan, shriek) Donald motherf**ing Trump is actually really the president of the USA, and it's not a joke or a nightmare (well it is a joke and a nightmare figuratively speaking...), I don't see why anyone should be excluded from attempting to be a leader. It's up to us to vote for people and values that are not stupid. There is some truth to the idea that we get what we deserve.