Complex sentence: Aware that the Soviet military was the only institution that could successfully obstruct his quest for, Stalin set out to "liquidate" Tukhachevsky and seven other senior commanders, and his time, there was no disagreement from his inner circle.
Split into simpler sentences: Aware that the Soviet military was the only institution which could successfully obstruct his quest for, Stalin set out to "liquidate" Tukhachevsky and seven other senior commanders. This time, there was no disagreement from his inner circle.