By measuring foreign policy assertion, we document that Danish and Swedish Russia policies have fluctuated widely in the 21st century, as well as in relation to each other. Specifically, big assertion leaps took place in 2002 (Denmark) and 2008 (Sweden). Having conceptualised and operationalised small state assertion, we proceed to the explanation of these leaps. The same factor turns out to be the efficient explanation in both cases: an individual policy-maker’s so-called ‘lesson of the past’ – what he believes ‘history teaches us’. It is shown how existing theory of lessons of the past can contribute to the understanding of small state assertion in asymmetrical dyads, but only if the proper permissive circumstances are identified. First and foremost these amount to the presence of a reasonable foreign policy action space.