József Mindszenty, at one point prince primate of Hungary, archbishop of Esztergom and cardinal, is still a controversial figure. According to some he was a principled man who to the last minute defended his church and his rights, but there are others who think that József Mindszenty did a great deal of harm to the church he thought he was defending.
He was born József Pehm in 1892 in Csehimindszent (Vas county), then population 900. According to his brief biography on the internet he was arrested on February 19, 1919, that is before the establishment of the Hungarian Soviet Republic, and held until the fall of the Béla Kun government on August 1, 1919.
He made quite a career for himself in the Horthy regime and on March 25, 1944, he was consecrated bishop of Veszprém. In November he was arrested for his opposition to the Arrow Cross government and charged with treason. It was in April 1945 that he was released. On Septemer 15, 1945, he was appointed prince primate of Hungary and archbishop of Esztergom.
He was arrested at the end of 1948, accused of treason and conspiracy, and in February 1949 was sentenced to life imprisonment. During the October Revolution of 1956 a group of soldiers freed him from jail, but a few days later he sought refuge at the U.S. Embassy where he stayed for fifteen years. Eventually a compromise was worked out between the Vatican and the Hungarian communist government. Pope Paul VI declared Mindszenty a "victim of history" (intead of communism) and annulled the excommunication his predecessor declared on all persons involved in his trial and conviction. In turn, the Hungarian government allowed Mindszenty to leave the country. First, Mindszenty had to resign as prince primate of Hungary and later he was stripped of all his titles by the pope. In return, the pope didn't appoint a new archbishop of Esztergom until Mindszenty was dead.
These are more or less the bare facts. The recently released book (in Hungarian) by András Kanyó, a journalist, entitled Administering Justice: The Other Side of Mindszenty (2010) expands on Mindszenty's political predilections. From an early age Mindszenty was an arch-conservative who even opposed the democratic revolution of Mihály Károlyi. Later in the 1930s he was attracted to the radical right, but in the end he turned against Ferenc Szálasi and his henchmen. One reason for his aversion to the radical right may have been the fact that he was a steadfast legitimist throughout his life, so he found even the Horthy regime not quite legitimate. During this period and even later he refused to recognize that the revival of Habsburg rule in Hungary was out of the realm of possibilities.
After his appointment by the also extremely conservative Pius XII as prince primate he lost his sense of political reality. He blindly followed his own interpretation of an unwritten constitution according to which the prince primate was the deputy of the king in the latter's absence. Thus, he didn't recognize parliament's declaration of Hungary as a republic on February 1, 1946. He opposed not only communism but also the new democratic coalition government and the republic. For most democratically minded people those were the years of hope, hope that was of course dashed by the communist takeover.
As for the charge of treason, it all depends on how you define treason. He did visit the American embassy a few times and tried to convince the Americans to intervene, but the American ambassador made it clear that the United States doesn't meddle in the internal affairs of other countries. Certainly that wasn't an act of treason; it simply showed Mindszenty to be an obstinate man who paid not the slightest attention to diplomacy. Not long before his arrest he told a reporter of The Daily Mail that he would urge American-British military intervention. When the journalist remarked that such a move would most likely lead to a nuclear war, Mindszenty apparently said that "even that would be better than bolshevism." That gives us an idea about Mindszenty's single-minded preoccupation with communism.
Pope Paul VI said of him: "Mindszenty was an obstinate man who was difficult to handle. Many of his activities were hard to understand." One thing we can understand: József Mindszenty was an arch-conservative who was against anything that to him smacked of modernity or liberalism.
Whether a more pliable man at the head of the Hungarian Catholic Church would have been more successful at saving what little could have been saved under the circumstances is hard to say, but I believe that his absolutely unmovable position on certain issues, including ones that had nothing to do with communism, was detrimental to the Hungarian Catholic Church. Nonetheless, as might be expected, a revival of Mindszenty's veneration as the defender of the faith is under way.