While being both the head of state and head of the government is very taxing and time consuming, I feel that they can continue to be held by the same person. The American President has historically had both duties and has been able to do both.
I suppose it's possible, but it isn't guaranteed. The reference to the British monarchy and government highlights the possibilities and the problems. Queen Elizabeth II is respected by all, even those Brits who feel the monarchy is an anachronism; but my understanding is that even those who truly adore it anticipate major changes in the position and responsibilities of the royal family after her death.
How much does the presence of the royals affect the performance of the Prime Minister? Depends on the PM.
I believe so. By relieving the country's executive leader of some of the ceremonious and also time-wasting aspects of being head of state, the monarch or other leader provides cover to allow the executive leader more time to focus on the country's actual problems. By decoupling ceremony from the hard work of running a country, the symbolic leader makes the real leader more effective.
In my opinion, I do not see that a symbolic head of state, or a non-executive head of state, such as Elizabeth II of England, is able to make an elected leader more effective. The fact that the head of state is symbolic means that the monarch holds very little power. This person is more like a figurehead.
In England, the Prime Minister may direct and oversee the Parliament, but the real power lies with Parliament, and has done so since 1649, when England's Charles I was arrested and executed for high treason. There was no monarch on the throne from 1649 until 1660. In place of a king or queen, the Parliament became the ruling body...
The monarch was then abolished and a republic called the Commonwealth of England…
…was formed, also known as the Protectorate—ruled for the most part by Oliver Cromwell until his death. When Charles II returned from exile, he became king, but never again would the English monarchy have the power that had been taken by Parliament.
With this is mind, it seems very unlikely that Elizabeth II is able to offer any political aid to the Prime Minister. Elizabeth II is a very public figure and the role of the monarch in English history even after the death of Charles I has been very important to the people of England perhaps from a traditional standpoint. The non-executive head of state may be highly visible, but does not wield the power to assist the elected leader in being more effective.
It seems like you are asking if having a president and a monarch improves things. In the case of England, the monarchy is mostly figurative. I think that monarchy in general is an old-fashioned concept and will not add stability. The idea that a person is born into a position of power does not mean that the state will be more stable, just that the state is susceptible to the whim of the genetic line.
In a very limited sense, from my point of view. Yes, loyalty to or at least the popularity of a monarch can also generate more loyalty to the government in general, and in so doing stabilize a nation's leadership and institutions.
That being said, the public knows they are figureheads, and I think they easily separate the actions and the credibility of government from those of the royal family.
Well, as a Brit I can say that the figurehead can have power in terms of supporting an elected government but only is as much as the monarchy still holds power in the popular imagination of the people. A very important political part of taking power is for the new Prime Minister to go to Buckingham Palace and be invited to form a government in the House of Commons. The monarch will never refuse the winner of the election the right to do so, but in a country like Britain where tradition is so important, this is still a vital part of the procedure.
In my opinion, no. In fact, I would argue the opposite. I would say that the existence of the symbolic head of state actually reduces the elected head of government's effectiveness.
Look at it this way -- in the United States, the President is both Head of State and Head of Government. This, to me, actually gives the President more credibility with the people than he would have if he were only the Head of Government. Because he is the Head of State, he gets to act in a variety of symbolically important ways where he gets to look like a good guy and a symbol of the nation as a whole.
By contrast, a Prime Minister in a system like Britain's has fewer such opportunities. Such a leader does not have as many opportunities to look like a leader of all the people. Instead, he always looks like someone who is "just" an elected politician.
However, not everyone agrees with me. Please follow the link for a discussion of why having a figurehead can be of help. I must say, though, that that discussion does not really argue that the elected leader would be more effective -- just that the country's system as a whole would be more stable.
I am not certain that there can be an absolute answer to this question. I do believe that some level of public sway can be held by the symbolic leader or figurehead that can make the elected leader's life a bit easier or more difficult. I am not entirely convinced that the figurehead holds much in way of definite and definable power. Yet, I believe that their symbolic status can help give some level of public support to the elected leader. It might prove difficult for the elected leader to be in direct and total opposition to the symbolic head of state. The elected leader might not have to completely integrate the symbolic head of state into policy making decisions. Yet, in nations whose history values the symbolic head of state, it might be in the best interest of the elected leader to ensure that they have the blessings or the consent, or at the very least the lack of opposition, of the figurehead leader.