I study the German occupation of the USSR during WWII, but focus on Russian soil. I can say that wherever possible, important people were evacuated eastward by the soviet forces. The closer they were to the front lines, the less time and opportunity there was to pack up and leave, so the more likely these people were to remain trapped. Anyone who was a member of the Communist Party, but particularly high ranking members, would've been the first to be evacuated. As for those who remained, there were different possibilities. Timothy Snyder wrote in his very recent book Black Earth that most Communists who ended up in occupied territories switch sides and worked for and with the Germans. He offers very minimal evidence and few citations to back up this claim, however. Previous studies focussing on the territories that had been added to the Soviet Union in 1939 – meaning western Ukraine, formerly eastern Poland, as well as the Baltics-- suggest that many people who joined the Communist Party or took positions of power under the Communists in these territories were pragmatically seeking power, and so many did switch sides or work for the Germans for the same reason. However, there is also evidence that Communists were seen as dangerous and untrustworthy, particularly by the German army. In some places they were targets of arrest and even murder. Therefore, it is very unlikely that there was one single experience for all communists who remained in occupied territory. Hopefully someone else can offer some insight into whether governments of SSRs that made it out alive were reconstituted and carried on their work in evacuation. EDIT: Just learned how to italicize, fixed book title.