The future Paul VI, Monsignor Giovanni Battista Montini, directly betrayed Catholic priests sent behind the Iron Curtain by Pope Pius XII, effectively sentencing these priests to death or imprisonment:An elderly gentleman from Paris who worked as an official interpreter for high-level clerics at the Vatican in the early 1950s told this writer that the Soviets blackmailed Montini into revealing the names of priests whom the Vatican had clandestinely sent behind the Iron Curtain to minister to Catholics in the Soviet Union during the Cold War. The Soviet secret police were on hand as soon as the priests crossed over the Russian border and the priest infiltrators were either shot or sent to the gulag.
The extent to which Pope Paul VI was subject to blackmail by the enemies of the Church will probably never be known. It may be that, in so far as the Communists and the Socialists were concerned, blackmail was entirely unnecessary given Montini's cradle to grave fascination and affinity for the Left. On the other hand, the Italian Freemasons, M16, the OSS and later the CIA and the Mafia were likely to have used blackmail and extortion against Montini beginning early in his career as a junior diplomat, then as Archbishop of Milan and finally as Pope Paul VI. (Randy Engel, The Rite of Sodomy, p.1156.)
Giovanni Montini/Paul VI engaged in a policy of Communist surrender known as Ostpolik (East politics) wherein he appointed men as "bishops" in Communist countries behind the Iron Curtain who were friendly to, if not actual agents of, the Communist authorities in those countries. These "bishops" had a perverse "apostolic mandate," if you will, given then sub secreto by Montini: never criticize Communism or any Communist officials. In other words, be good stooges for various "people's" and "democratic" republics in exchange for promoting the false "gospel" of conciliarism.
It was also Montini/Paul VI who sold out the courageous Jozsef Cardinal Mindszenty, the Primate of Hungary and the Archbishop of Budapest, Josef Cardinal Mindszenty when the latter, after taking refuge in the American Embassy in Budapest for a decade following the Hungarian Revolution in October of 1956, was forced out of the American Embassy as a result of Vatican pressure and then, after being told by Montini/Paul VI that he remained as the Archbishop of Budapest, has his primatial see declared vacant by the theologically, liturgically and morally corrupt Montini.