The driftwood theory (Finnish: ajopuuteoria, Swedish: drivvedsteorin) states that Finland's involvement in the Second World War was the consequence of inadvertent decisions made on the basis of a limited choice of policies, emphasizing its reactive stance rather than inherent aggression.
During the war, the German ambassador Wipert von Blücher had written in 1950 that Finland had been at the great powers' mercy, entirely without the possibility of an independent political solution.
In his memoirs, Blücher used the analogy of a piece of driftwood to describe Finland's situation: "In the battle of great powers the free will of small states has very narrow limits.
The theory was popular in Finnish historiography after the war, but, it has since been shown not to correspond to historical events, since the closer relationship with Germany had begun as the result of an informed choice.
For example, Finnish president Urho Kekkonen was opposed by the majority of the right-wing press when he agreed to Krosby's thesis in 1974, at the 30th anniversary of the war's ending.