Author:  Paul Hollander Paul Hollander is professor emeritus of sociology at the University of Massachusetts, Amherst and an associate of the Davis Center for Russian and Eurasian Studies at Harvard University. He grew up in Hungary which he left after the Revolution of 1956. Educated at the London School of Economics (B.A.) and Princeton University (Ph.D.) he is the author or editor of 14 books.

The single major precondition of the establishment of a communist system in Hungary was the arrival and prolonged presence of Soviet troops during and after World War II.

Hungary had belonged to the Axis powers, was an ally of Nazi Germany, sent troops to fight in the Soviet front and German troops were stationed in Hungary beginning March 1944. In the course of pushing German forces westward the Red Army entered Hungary in the Fall of 1944 and by early April expelled the German troops and their Hungarian allies. Soviet troops stayed in Hungary until 1990.