Original sentence: Two of Gordievsky's most important contributions were averting a potential nuclear confrontation with Russia when NATO exercise Able Archer 83 was mis-interpreted by the Soviets as a potential first strike, and identifying Mikhail Gorbachev as the Soviet heir apparent long before he came to prominence
Edited sentence: Two of Gordievsky's most important contributions to making the world a safer place were in averting a potential nuclear confrontation with Russia when NATO exercise Able Archer 83 was mis-interpreted by the Soviets as a potential first strike and identifying Mikhail Gorbachev as the Soviet heir apparent long before he came to prominence