False.
The embargo of wheat destined for Russia as a political response to the Russian invasion of Afghanistan was not a failed unilateral use of export controls. In fact, this embargo was implemented by the United States in response to the Soviet Union's invasion of Afghanistan in 1979. It was part of a broader set of economic sanctions imposed by the United States and other countries to protest and condemn the Soviet invasion.
The embargo was a coordinated effort by multiple nations, rather than a unilateral action, and it was not considered a failure but rather a diplomatic and economic response to the geopolitical situation at the time.