[quote=@Vilageidiotx] You would also most likely have problems with illegal immigrations and crime along the border, but since your border with Finland is so small and rough, it's unlikely that crime would amount to much more than smuggling or maybe a little light farmer-robbing/cattle rustling. 
[/quote]

And there isn't much up there for either party in the first place. Northern Sweden and Finland as I've gathered is a rough place, and even under a Communist government I'd think the local Sami tribes just do not give a shit and will keep doing as they do. The government would be more occupied with the urban areas and Southern Finland.

As per Southern Finland's quality: that's unexplored. They are out of their mines in the north, and southern Finland is pretty much swamp. Hell, Finland in general about this time is already a second-class European nation. You're looking at a nation that'd still be incredibly young, and pitted with scars of Revolution from both Russia and Communists.