Complex sentence: Mussolini, while using the trials at his advantage, was concerned by the whole story, and when the case itself turned out to be a divisive issue among clericals and liberals, he intervened trying to reduce its exposition on the national mass media.
Split into simpler sentences: Mussolini, while using the trials to his advantage, was concerned by the whole matter. When the case itself turned out to be a divisive issue among clerics and liberals, he intervened, trying to reduce its exposure in the national mass media.