Complex sentence: Czarist Russia was suspicious of the movement's potential to stir up native unrest and perhaps involve outside powers; the Soviet authorities ultimately suppressed it for fear of its potential to unify Siberian Turkic speakers under a common nationalism.
Split into simpler sentences: Czarist Russia was suspicious of the movement's potential to stir up native unrest and perhaps involve outside powers. The Soviet authorities ultimately suppressed it for fear of its potential to unify Siberian Turkic speakers under a common nationalism.