If one looks at some of the Internet sites in search of the Doctrine of the Holy Crown they seem to be written mostly by people who are perhaps a bit too close to the idea itself and hence all start with the same story. According to popular tradition during the coronation ceremony Stephen held up the crown to offer it to the Virgin Mary in order to seal a divine contract between her and the crown. According to this version the Hungarian crown was not only holy but from the beginning it was the symbol of the country. Moreover, the crown represented the legitimacy of the ruler and that legitimacy was given by the Hungarian people as represented by their leaders, the nobility.
I rely on a different source that I find a great deal more credible. The Doctrine of the Holy Crown was first articulated in the so-called Tripartitum, a summary of Hungarian common law written in 1514-1515. The author was István Werbőczy, a jurist, chancellor and later nádor, the highest office in the land after the king who could fill in for the king in his absence.
The popular story about Stephen's offering the crown to the Virgin Mary is absent from the Tripartitum. Whether the story has any historical basis is questionable, though the cult of Mary started in Byzantium and moved westward, reaching Hungary about this time. The Virgin Mary has a special status in both Hungarian and Polish history. But whatever the case, the Doctrine of the Holy Crown is fundamentally a secular, legal principle about power, not a religious one.
Werbőczy stated that "there is no prince but only as chosen by the nobility and there is no noble, only those who have received their nobility from the king." This is about as close to a populist view of kingship as was possible in the sixteenth century. And it has nothing whatever to do with Stephen. Stephen was not chosen by the nobility, and he didn't receive his power from the community. The crown was the symbol of the state and had religious significance, but the crown belonged to the king and to him alone. Moreover, the king owned the land, and the church and the nobility received land as gifts for services rendered. Even as late as King Matthew (Corvinus, fifteenth century) there was never any question that the crown could be "democratized." Only at times of interregnums or during reigns of weak kings did the idea surface that somehow through the coronation ceremony the nobility endowed the king with the right to rule.
During Werbőczy's time the power of the king was perhaps never so weak, and therefore it is not surprising that it was during this time that the doctrine became part of a legal codex. The codex assembled by Werbőczy never became law because, although the Diet (parliament) voted for its acceptance, the king refused to countersign it. King Ulászló II may have been weak but he was no fool. However, the provisions of the Tripartitum became law in Transylvania when it became a separate entity, the Principality of Transylvania (or in Hungarian, Erdélyi fejedelemség). Although Werbőczy's codex didn't become the basis of official Hungarian law, it had an enormous influence on the Hungarian legal system. Unfortunately, that influence was not beneficial. It was really a compilation of "nobilities' common law." It didn't follow the legal practices of the western European monarchies but relied heavily on feudal practices. Thus the Tripartitum became an obstacle to the development of a modern middle class.
Even after 1848 and 1867 the Doctrine of the Holy Crown remained an integral part of political thinking. By that time the Holy Crown was not only the symbol of a contract between the king and the nobility but, with the freeing of the serfs, the Holy Crown became the symbol of a contract between the king and the population of Hungary as a whole (including of course the non-Magyar citizens). The Doctrine of the Holy Crown assumed a transformative role between the two world wars when Hungary was a kingdom without a king (1920-1946). For example, verdicts in Hungarian courts were brought in "the name of the Holy Crown." But one must add that the soldiers swore loyalty not to the crown but to Miklós Horthy, head of the Hungarian armed forces.
Why the sudden enthusiasm in certain circles for the Doctrine of the Holy Crown? Although the proponents of the doctrine wouldn't admit it, I think that the most important consideration is that the Holy Crown in its modern interpretation symbolizes the whole of historic Hungary. The doctrine was used between the two world wars for purposes of irredentism and today I think it serves a similar role. You're not going to hear this from the proponents themselves, but here and there the truth slips out.
For instance, when Alfréd Pócs, our shaman-doctor, talked about his activities at the gasfields at Makó and insisted that the Hungarian government should undertake the exploration, he was reminded by the reporter that Hungary doesn't have enough money to extract the gas from the field; the gas can be very deep underground. Dr. Pócs, a great believer in the Doctrine of the Holy Crown, responded that the Canadian exploration company already uses Croatian workers to dig the wells, and he knows that the Croats would immediately join Hungary again just like before 1918 if the Holy Crown ruled the land. I am sure Dr. Pócs had an even greater vision–the lands of the Holy Crown in their entirety.
Another source for the popularity of the Doctrine of the Holy Crown may be some people's religiosity. I think here of our other doctor, Lajos Papp, who is apparently a deeply religious man, although I'm not sure whether his views fall within mainstream Catholicism.
Most people who appeal to the Doctrine of the Holy Crown probably haven't got the faintest idea what they are talking about. They just hear their leaders refer to the crown and that somehow resonates with their anti-government feelings. I wish some sociologist would undertake an in-depth study of what is behind the popularity of the doctrine in far-right, nationalistic circles since here I'm just offering hypotheses.