It is perhaps not recognised as often as it should be that Lenin, and Stalin following him, were fully in favour of Finnish secession and independence:
‘There is at present a movement in Finland for securing national freedom, and there is also the fight waged against it by the Provisional Government. The question arises, who are we to support? Either we are for the policy of the Provisional Government, the forcible retention of Finland and the reduction of her rights to a minimum—in which case we are annexationists, for we are bringing grist to the mill of the Provisional Government; or we are for independence for Finland. We must express ourselves definitely one way or the other; we cannot limit ourselves to a statement of rights …
‘We must support every movement directed against imperialism. Otherwise what will the Finnish workers say of us?’
‘The Seventh (April) Conference of the R.S.D.L.P. (Bolsheviks) April 24-29, 1917’. Collected Works, vol. 3, pp. 58-60.