With close reference to the play The Caucasian Chalk Circle, what was going on that caused Brecht to edit his manuscript?

The first edition of The Caucasian Chalk Circle was mostly true to the German text with the only serious omission being that of the Prologue. The reason for this omission is related to the fact that Brecht was forced to appear before the House Un-American Activities Committee in Washington in October, 1947. Since the play was about to be published at this time, the publication of the Prologue was postponed at his request.