Monarchy originated because warriors needed a war leader. Sometimes this person was elected, sometimes he inherited the job from his father. Over time this leader liked the position and established a dynasty so that his family held power. These dynasties have been a mixed blessing. An inept sovereign could lose the control already established by his forebears which led to wars and attempts at dominance in other ways. This suggests that the eldest son inheriting the crown is not necessarily the most effective way of using a royal family’s skills.
Most modern monarchies are constitutional. This means they are figureheads of State without real power. The power lies with the politicians in Parliaments. In this case the monarch is a focal point for the nation concerned, a rallying point in good times and bad.
During the second World War, when Buckingham Palace was bombed, the then Queen Elizabeth said she could now look the east enders in they eye. The east end of London was a region which had been heavily bombed.
With a monarch comes a family. When members of the family misbehave it causes a loss of respect for the institution of monarchy. While the public is a fickle body, they do expect their representatives to behave in mature and dignified ways. In the British Isles, the Queen has maintained the respect of the populace even when she has seemed to be remote and distant. This is because she always behaves with dignity and works hard.
The argument against a monarchy could be the amount of money it costs to maintain. However, if the figures are matched with any other type of Head of State the costs are probably similar. In the British Isles, the Queen now pays income tax and the Duchy of Cornwall (the Prince of Wales’ domain) gives considerable amounts to charity.
There is also the issue of status. By an accident of birth, one group of people maintain a position in society which many find unacceptable. With that status usually goes huge incomes and possession of large areas of land. The privileges attached to titles and the power that comes with them is seen by many as unfair, undemocratic. The difficulty is that humans follow patterns. There is always someone who rises to the top, likes to have medals and privileges and being in a position of authority. Even in countries which are not monarchies there is a jockeying for position and power. Those who earn riches infiltrate the powerful group. The monarchy does not change that.
At the moment the current European monarchies seem to be popular and well supported by their countrymen. With modern technology, if they are seen to be behaving in a way which the nation does not like, they are very quickly informed. The recent wedding of Prince William and Kate Middleton was a popular event because it seems to be a love match and fulfills the romantic ideas most people seem to have about royalty. Perhaps children’s stories are to blame.
The main argument against monarchy is the privileges which are unearned. The cost of unimportant people, because they happen to be related to the sovereign, is also a bone of contention. In the British Isles, these side issues are being whittled away and minor members of the royal family have to earn their living like anyone else.