The loss of Sveaborg opened the Finnish coast and Åland route to the Russians. They could move through the islands and then cross the Baltic ice to a point about 70 kilometres north of Stockholm. Winter had first neutralized Swedish sea power and now converted the same water into a direct invasion route. The threat to the capital turned the campaign in Finland into an immediate danger to Sweden itself. It pushed Sweden toward negotiations and the end of the war.
Chapter · 44:02-44:42
The Åland ice road brought Russian troops within 70 kilometres of Stockholm
The Russian approach across the Åland Islands and Baltic ice turned the loss of Sveaborg into a direct threat to the Swedish capital.