Personally I think that award belongs to the United Kingdom. They don’t even need a constitution.

To ensure the moneyed classes of Britain are well looked after, they have both a king who is a billionaire and a prime minister whose net worth is a more modest $500 million.

The King is irrelevant and the PM got his money by marrying an heiress. No, it's true that money is a problem, but those are the wrong places to look. Try https://www.transparency.org.uk/can-you-buy-lordship or https://news.sky.com/story/michelle-mone-who-is-she-and-what...