The services of propagandists, in medieval as in modern times, are required primarily by rulers and those who want to become rulers. Why does a ruler need propaganda? First and most important, he needs it to convince his own subjects of his right to rule and of the rightness of his way of ruling, that is to say, to demonstrate that he is neither a usurper nor a tyrant. It is, of course, primarily those who in fact are usurpers or tyrants or both who need such a demonstration. Legitimate rulers, whether by election or by succession, have little need of propaganda to justify their rule, though they may require it for specific policies. Another task for a ruler's propagandists, again more particularly those of rulers who have seized power by force, is to influence or, where appropriate, to subvert the subjects of other rulers, whether friendly, neutral, or hostile.
Propaganda of one sort or another is always needed by governments at war. This is not limited to a state of shooting war. It applies equally—perhaps even to a greater extent—in time of what we have become accustomed to call "cold war," when countries without formal declaration or the involvement of regular armies make war against each other by propaganda and terror. Terror indeed is, in this sense, a form of propaganda.
Every modern army has a core of professionals; every war brings a surge of enthusiastic, often unskilled volunteers. The professionals are just doing their job. The volunteers respond to the call of blood or faith, and for them their cause is always just, their side is always right, their ultimate victory foreordained. But in many countries, the modern army also includes great numbers of often reluctant conscripts, who are neither following a profession nor inspired by a cause. These need to be persuaded that their fight is good and necessary and—perhaps most important of all—has a reasonable chance of success. This task of persuasion becomes at once more urgent and more difficult at a time when increasing numbers of conscripts are literate, with access to other information and ideas besides those provided by their military superiors. Today, they do not even need to be literate to have access to such other information and ideas. All that is necessary is a portable radio. If it is a short-wave radio, it exposes its owner and his comrades to propaganda from all over the world.
Conscription is very far from democracy; indeed, in some respects it is the very converse of democracy. Yet the two have certain features in common. Both involve the great mass of the population in the processes of government and the structure of power, previously reserved to a small elite; both, in so doing, empower ordinary people by placing in their hands the means of change—conscription by weapons, democracy by votes. Systems using both tools of governing therefore need to resort to persuasion, that is, to propaganda, to ensure that those weapons or votes are used in the way that they would wish.
At the present day in the Middle East, countries that maintain large conscript armies are heavily engaged in propaganda. Those that rely on professionals and volunteers can afford to take a more relaxed attitude.
Propagandists would also be required by a contender in a civil war or a revolution, in a disputed succession, or any other form of internal strife. Obvious examples are tribal, regional and sectarian rivalries. Propaganda on behalf of employers other than a holder or seeker of power is rare in Middle Eastern history, but it is not unknown, and there are several interesting examples which prefigure modern developments.