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Thank you.

I'd say so.

-Mongol doctrine in Genghis Khan's age was based heavily on terror. It was fairly successful (although, obviously, not universally so) in securing submission from various states, such as Korea and the Principality of Antioch.

-Vlad Tepes' mass impalements may have been successful in shaking Sultan Mehmed II enough that he abandoned his invasion of Wallachia.

-The terror caused by U.S. use of atomic bombs on Japan were likely a factor -- although not the sole factor, considering the overall trajectory of the war, the entry of the Soviets, etc -- in inducing Japanese capitulation.

This isn't to say that fear-based tactics were universally successful -- for example, the Axis attempt to break British morale and Allied attempt to break German morale through terror bombing in WW2 was largely unsuccessful. I'm not sure whether there's an agreed upon view on when and why fear is successful or unsuccessful.