History shows that diplomatic recognition of extremist governments can make them more likely to moderate their behaviour. While pariahs are able behave with impunity, when brought within the international system, they become subject to constraints. The most striking example of this was the Soviet Union…

Shunned by the international community, the Bolsheviks acted in much the same way as Isis do now. Thousands of churches and priceless historical artefacts were destroyed in the name of an extremist ideology. Firing squads roamed the countryside brutally executing enemies of the regime. Similarly to Isis, Russia’s new rulers recognised neither the legitimacy of neighbouring governments nor the sanctity of their borders. For example, the Communist International explicitly sought to export world revolution and sponsored armed uprisings in Germany, Hungary and Estonia.

Britain finally established diplomatic relations in 1924; nearly a decade passed before the US and most of the rest of the world followed suit. Widespread diplomatic recognition of the USSR did little to quell the internal excesses of the regime. But it did correspond to a shift in Soviet foreign policy from ideological zealotry to greater pragmatism and accommodation with its neighbours.